Generally speaking, I don't go around trying to advertise my writings on this website. I put notices up on the front page, and I will usually post a notice of some kind at Realms Beyond, and that's about the extent of what I usually do. Someone stuck a link to this website up on the front page of CivFanatics when Civ5 came up, without any prompting from me. I was pretty surprised when I saw that! 
I've also seen other people linking to some of my reports on various Civilization websites, usually when they have some point to illustrate.
I bring this up because there was a poster at CivFanatics who called me out on my Art of Wu game, when another individual (not me!) linked to it in a forum thread. This poster claimed that I had lied about the starting position, and actually had generated something like a dozen starts, only picking the best one. Leaving aside that that simply wasn't true, this poster also went on to claim that the city spam tactics I emphasized would only work on a map with very strong terrain, and that I was unfairly branding Civ5 with my claims. I was somewhat irritated by that person, and I set out to prove them wrong with this game.
I was also inspired by two other threads at CivFanatics played by other individuals thinking along the same lines as me. The first was the "ICS Civ5 Style" thread created by pi-r8 (luddite at Realms Beyond), in which he made great use of the Liberty and Order social policy trees to create a massive French empire. I thought that luddite's game was extremely well played, and wanted to try a variation off of the basic idea with some of my own tweaks. The second game was alpaca's "Rome Infinite Style" thread, in which he took the Romans and expanded to a monstrous size within the first 200 turns. Both games were played on Immortal setting, and featured different ways to build gigantic empires that could curb-stomp the AIs at will. Before reading this game, I highly encourage you to take a look at the two of them. Luddite's is really short and can be knocked out in one minute or two, alpaca provides a narrative as long as one of my games.
Because I wanted to follow luddite's general build, I would be playing as France in this game, once again on Immortal difficulty. For some variation I chose the Small Continents map script, although with Low sea levels to avoid getting a map full of little islands. After the griefing I took from rolling a single additional start last time, I took the first one offered by the game. This was what I found:
Paris was founded in what I would consider a relatively weak position. No river for the extra commerce and Civil Service farming bonus. On the coast but with no seafood resources to help out. (Water tiles are seriously terrible in this game, you almost never want to be working 1/0/1 tiles.) Only one food bonus of any kind, a cattle resource three tiles away, which I would have to spend money to purchase. The silver resource was obviously nice, although the incense was kind of a dud, it being one of the weaker luxuries in this game. I wished very badly that I had started about four tiles to the west, in that nice-looking river valley! Keep in mind though, that none of that was visible on the first turn, and I'm not omniscient while playing. Just have to make due as best I could with what I had here.
I started out with my standard Civ5 build of scout, worker, settler. Early growth was very slow without a single tile bonus of any kind in the city's starting radius. (I guess the sheep count, sort of... but they were only 1/2/0 in terms of yield!) Notice how just the two units above are nearly bankrupting my civ; the river starts are simply enormously better than the non-river ones. The good news was that I had found two nearby city states, and one of them happened to be maritime! The bad news was that I had also found Alexander, or he had found me, rather, which meant that warfare of some kind was inevitable in my future. I was kind of hoping that I would have my own fair-sized island to practice my rapid expansion strategy in peace. Not to be in this game though, it seemed.
Scouts explore terrain quickly with their terrain movement bonus. I soon found the location of Alex's capital:
Wow - I hope he likes it cold! My scout doubled back and explored the northern wastelands on his return trip, confirming that most of the land between us was nothing but snow and ice. I assumed that I was stuck on an island here alone with Alex, but that ultimately turned out to be false, as Bismarck would show up soon with some scouting units of his own. As it turned out, there was a large patch of desert to the southwest of Athens, and then eventually several more civilizations in the deep south far, far away from my corner of the world. Here's a larger picture of the surrounding terrain:
You can see how everything north of Paris and Orleans was a desolate expanse of frozen tundra. A lot of the land up there was actually snow, which doesn't even yield the one food that tundra provides. I had a little area down here in the south which wasn't too bad, with exactly one river at my disposal, and everything else was pretty much garbage. Well.... you know what? That's perfect for what I was trying to accomplish here. No one will ever be able to say that I won because I had land that was "too good" given the local neighborhood in this game. I will use this land to maximum extent, and I will see if I can out-build the AI on Immortal!
...after I deal with Alex, of course. See the Horseback Riding research? I have horses on hand, and that alone should be enough to wipe the Greeks off the face of the earth. There's absolutely no chance that I can work peacefully with Alex. I've played enough of Civ5 to know how the AIs work, and they will never be your friends. They get mad at everything that you do, and eventually they will nearly always declare war. The only way to stop that is to have an army that's much larger than theirs, which isn't happening on this difficulty level. So in order to fulfill my building goals for this game, I must first "clear out" some space and bushwhack the Greek Empire. Note: the Greeks have the best Ancient Age unique units in the whole game. Ah well, if it were easy, they wouldn't call this "Immortal"!
Over the next few turns I completed my second worker and continued research into Horseback Riding tech. (I almost certainly could have stolen a worker from useless militaristic city state Dublin, but I have taken that off the table in my games now. It's cheezy and exploitative.) During this period, I was able to raise some extra money by selling my Open Borders to Bismarck for 50g, who was a million miles away and gained nothing from the deal. Free money, thanks bud! Remember, always sell your stuff constantly to the AI for cash in the early game. I was also able to take advantage of France's extremely strong civ ability:
France receives 2 culture/turn in every single city until the discovery of Steam Power tech in the Industrial Age. This culture both unlocks social policies more quickly and allows cities to expand their borders more rapidly. I regard it as one of the best civ abilities in the game, in the first tier along with Babylon, Greece, China, and Persia. Some people have criticized this ability online by looking at the total cultural output, and pointing out that France's ability is completely useless at the end of the game. These people are missing the point: France's ability enormously increases the rate at which you acquire social policies at the start of the game, and that's what matters. Recall that in Civ4, the true value of the Philosophical trait was that it produced the *FIRST* Great Person twice as fast. In Civ5, you normally start the game with 1 culture/turn from the capital's palace. France starts the game with 3 culture/turn from its civ ability, thus gaining policies at triple the normal rate! Granted, that won't last forever, but the value of buying starting policies earlier (when you have fewer cities and they are each cheaper) is not to be denied. France's ability also scales up extremely well with swarms of small cities, making France another excellent choice for a game of mass expansion.
In the picture above, I am already selecting my third social policy a mere 45 turns into the game. I have already taken the default Liberty policy (50% production bonus when training settlers) and the "Citizenship" policy (25% faster worker speed). However, these are mere pre-requisites for Meritocracy, which grants +1 happy face for every city connected to the capital. This is one of the best policies in the entire game, as it essentially grants you an extra happy face in every single city. Normally, each city costs you 2 unhappy faces + city population in overall unhappiness. With Meritocracy, you can remove one of those unhappy faces for each and every city. Meritocracy is pretty much a must-have for any mass city strategy, and its appearance early in the game means that you can grab it before the policy costs start scaling up with more cities. Definitely take this one!
As for the rest of the Liberty tree, I'm not at all sure that "Representation" (+1 culture in all cities) is worth the cost. Yes, it does increase your culture, but keep in mind that every social policy that you take increases the cost of all of the following ones. You're essentially spending culture, delaying picking other policies, to bring in more culture. While I haven't run the numbers on this, my gut feeling is that it's probably not worth it, especially since Representation isn't a pre-requisite for anything else. On the other side of the tree, "Collective Rule" (new cities start with 50% of the food box full) is completely and utterly useless. Cities only need 15 food to grow from size 1 to size 2, and with maritime food your cities will grow like weeds at small sizes. Even without maritime city states, starting with 7 food in the box instead of 0 is pathetically underwhelming. Don't bother. "Republic" (+1 production in all cities) might be worthwhile if you didn't have to go through Collective Rule, but in its current state certainly isn't worth two social policies. You could put those two policies into Order and be only two policies away from Communism's +5 production in all cities, plus get good stuff on the way! Not worth it. Nevertheless, I still recommend going with Liberty for the incredible Meritocracy social policy. Take Liberty if you want to build, and Honor if you're going to war throughout the game. Do not take Tradition under any circumstances unless playing a One City Challenge. (For a hilarious guide on how *NOT* to play France with the Liberty tree, check out jobe's "Quick Expansion Strategy with France" article at Apolyton, which manages to get nearly everything possible wrong.)
The random empire ranking that popped up on Turn 50 rated Alexander as #1 in the game in military power, with my civilization ranked dead last. Alex had five times my military strength. I might actually be worried about that, if the AI wasn't so atrociously awful at combat in Civ5. Ten turns later, on Turn 60, we had reached the situation pictured above. I had founded a third city down on the southern coast in what looked to be the best location immediately available. Paris and Orleans had just finished a horseman each, exhausting my total supply, and were now adding a pair of archers to give me some ranged support. I also had my original starting warrior (upgraded to a spearman from a goody hut) and my earlier scout. Hopefully those six units would be enough to get the job done.
Meanwhile, Alex walked his settler eight tiles away from his capital so that he could plant it next to Orleans. Naturally, the very next turn he popped up in diplomacy and told me "I couldn't help but notice that you seem to be expanding into lands which I regard as mine." Uh-huh, right. You marched all that distance to plant a city right next to me, and then complained about my aggressive settling. 
Maybe this will get better in time, but at present the AI in this game is completely insane. Enough of this bull. Let's declare war and get rid of this joker.
Here's what I saw with my scout, my one horseman northwest of Orelans having already attacked and killed a Greek warrior. The AI did build a lot of warriors, which should fare very well on flat ground against my horsemen (strength 4 against strength 12). I actually screwed up here, as there was no tile that my scout could move back to safely. The AI correctly killed the unit the following turn, whoops! I had an extra visibility promotion on that unit, and it was silly to lose it through that kind of mistake. Anyway, I had little trouble mowing through the rest of the Greek units:
The archers were very helpful in taking down the one Greek hoplite, and softening up the warriors so that my horses wouldn't have to spend as much time healing. Orleans was able to bombard quite a few enemy units as well, when they mindlessly walked into range. I spent about a half-dozen turns here killing off the Greek field army, and then prepared to move on and capture Sparta. While I was in the process of doing that:
My spearman had snuck up to some Greek workers in the north and captured one of them. Then, while I was escorting that worker back to my territory, Alex moved another worker up next to my same spearman. 
This is the single dumbest thing that I have yet seen the AI do in combat, voluntarily moving a worker up next to an enemy combat unit with no defender. I captured this one as well, and now had four workers on hand. (I didn't build more than my initial two, knowing I would be able to capture some from Greece.) With that supreme stupidity out of the way, there was nothing to stop me from razing Sparta and then moving on Athens. It took a little while, because of the rough terrain, but of course I suffered zero further losses and captured the capital:
Alex had one more city remaining, Corinth down in the far southern desert. Rather than wipe him out now, I agreed to sign 10 turns of peace for Alex's treasury of 110 gold (after capturing the two workers in the above picture!) which would help fuel the purchase of my first maritime city state. I would come back shortly thereafter and eliminate the Greeks completely, mopping up the last city without issue. The AI simply has no counter right now to an intelligent combination of mounted and ranged units. Even Greece, with their super-spearman hoplites, fell easily to my little army of horses + archers. All that turning up the difficulty level does is increase the number of units that the AI produces, and even that doesn't help them all that much because only one unit can fit on a tile, and they tend to get in each other's way. It's unfortunate that the combat side of this game feels so unsatisfying at the moment (and Multiplayer against other humans lacks so many features that it's nearly unplayable).
Now the combat portion of the game was out of the way, and I had managed to secure unchallenged access to my corner of the starting continent. Here's what the situation looked like at Turn 100:
Even with the occupation penalty for Athens I was in excellent shape for happiness. That city brought me two new luxury resources, marble and ivory, and my alliance with the nearby maritime city state of Cape Town added spices to the mix. Along with colosseums enabled by Construction tech, I was set for a major period of expansion. Orleans would start another settler after its colosseum, taking me from four to six cities very quickly. (Incidentally, if you're wondering why there's a worker standing in the middle of the tundra up there, I literally had no tiles that needed to be improved, and fortifying up there at least kept the barbs from spawning! Once I added more cities, I put him right back on task again, and even needed more workers once magical maritime food started pumping up my population further.)
My Demographics numbers looked surprisingly good at this point in time; I did not expect to find myself in first place so easily! As it turned out, Bismarck's Germany had failed to expand at all, sitting around with just the capital, and that along with Alex's one remaining city pulled down those "Average" numbers significantly. I was also fortunate that no runaway AI happened to develop early on in this game, unlike my last one where France became the runaway. My continent extended far to the south, where the land was very evenly divided between Catherine and Hiawatha, the two of them balancing one another almost exactly. The final AI civ was Washington, who spawned on a fair-sized island and was thus unable to expand beyond seven or eight cities. With no runaways in sight breathing down on my neck, I could relax and get on with the real goal of this game: building a powerful empire of tight cities through rapid expansion.
Here's the theory behind Infinite City Sprawl, as written by alpaca in his Infinite Rome thread:
"The idea of an ICS strategy is to settle cities as close as possible to leverage the additional growth, production and commerce that small cities have over large ones. In Civ5, there are a number of game mechanics that lend themselves well to this kind of strategy. To wit:
1) Maritime city states. The bonus granted from maritime city states is per city. Each adds +2 food to the city tile at the start, increasing to +4 over the course of the game. Since every city benefits from this free food, a single maritime CS ally will allow you to set up two additional specialists in every in the later stages of the game. Obviously, the more cities the better, because each gets the bonus.
2) Happiness buildings. In Civ5, happiness is global... or is it? In fact, only the consumption of happiness is really global. The production is local. Each city can build happiness buildings, and the low-tier buildings are more efficient and more effective than the higher ones. If you have lots of small cities, each can have a Colosseum and a Circus where available, and some theatres. This actually rules out happiness as a long-term limiting factor and turns it into a growth-limiting factor because you need to set up these buildings in each new city.
3) Purchasing things with gold. Provided you have enough gold, you can buy buildings where and when you need them. Spamming trade posts is a typical strategy, and it's possibly even better in ICS. Just spam trade posts, make money, and buy the buildings you need. This is especially good for the more expensive buildings which have a better gold/hammer ratio.
4) Certain policies, like Communism and much of the Liberty tree, scale with the number of cities. So do some civilization abilities or buildings, like the one of Harun al-Rashid or the Chinese Paper Maker. For them, you also want as many cities as possible.
5) Research favors large empires because a tech will cost the same, no matter how many cities you have. Since having more cities usually means having more science, you will tech faster.
6) Trade route maintenance makes you want to put your cities as close together as possible. City tiles are free roads, after all.
There is a significant drawback to ICS which I won't hide from you: The speed of unlocking social policies. This is the only thing that is really better for small empires because, roughly, your average culture per city is what determines policy speed. Since there are sources of culture that don't scale with the number of cities, like wonders and cultural CS, you will be slower at unlocking these SPs, so make sure you only pick those which are most useful to you."
This was so well written that I wanted to repost it here for a larger reading audience. Well said! 
Due to all of these factors, having more cities is invariably a good thing in Civ5. More cities are always better. In fact, anyone who posts that you should pause or halt your expansion doesn't fully understand how this game works. You should always be expanding in Civ5, constantly, relentlessly, and never letting up, because each additional city makes your empire stronger. Happiness is not difficult to maintain once you understand what you're doing, and I'll explain more about how to do that later in this report. This is a major reason why I believe the Stonehenge wonder is a sucker's build in Civ5: oh sure, you get some extra culture for a policy or two, but it forces you to tie up that crucial early game production on a frivolous wonder instead of settlers or workers or horsemen to go smash the nearest AI civ. Don't waste your early production on wonders. Expand!
However, it's true that expansion and mass city spamming will limit the number of social policies that you unlock. While I don't view that as much of a disadvantage, it is something that you have to keep in mind. Even with tons of cities you can still unlock additional policies (as I'll show later in this report), they just won't arrive quite as fast. For this game, I wanted to experiment with luddite's use of the Order tree, in particular saving up culture for an early grab of Communism's amazing +5 production in every city. This meant that I would need to save up my culture for quite a long time (already in progress, as I hadn't picked any additional policies after Meritocracy) and that I would need to cap my expansion somewhat to prevent the costs of those Order policies from spiraling too far out of control. I figured that I would fill up the fertile part of my lands and leave the icy north until after I had Communism; that turned out to be seven total cities. The real expansion would come after that.
Finally, I also needed to get into the Industrial era in order to take those Order policies. Civ5's tech tree allows for some serious beelines on tech, especially when combined with Great Scientists to leap forward several techs at a time. Many people like to slingshot the bottom part of the tree and get the advanced military techs; you can jump straight from Gunpowder (680 beakers) through Metallurgy (900 beakers) to Rifling (1425 beakers) with a pair of Great Scientists, for example. My path would take the opposite approach and concentrate on the top part of the tree, gunning for Biology and skipping the entire bottom. With three Scientists, I could knock out Archaeology, Scientific Theory, and Biology (total cost: 4280 beakers) and research a mere three Renaissance techs. So this became the overall plan: fill out my starting core now, tech ahead to the Industrial era to grab the Order social policies, and then unleash the hounds and start expanding like mad. Time to put it in action.
My leftover horsemen were exploring the region in the deep south, beyond the desert near Athens. I found a pair of cultural city states there, Bucharest and Florence, next to a large chain of mountain peaks. Beyond those mountains was another large area of terrain, which contained the starting locations of the Russians and Iroquois. Germany was off to the west on a small peninsula, although at this point I had not found Bismarck yet. I dispersed a barbarian encampment and returned a captured worker to Bucharest (much too far away to keep the worker myself), resulting in 30 free influence. At that point I figured I might as well dump in another 500 gold for 70 more influence, taking me up to Allied status with Bucharest. Would have rather used that gold to befriend a maritime city state, but I hadn't found a second one. Now notice where my overall culture happened to be coming from. 12 of it was provided by Bucharest. Another 12 was simply the result of being France and having six cities, from my civ's natural ability. In other words, only 10 culture/turn was actually coming from city improvements, via five monuments, less than a third of the total. In many ways, hurling money at cultural city states is much more effective than building cultural stuff yourself, since you usually get a free luxury resource back in the process!
I continued to sell my resources every 30 turns for additional cash, making it easy to maintain Allied status with my two city states. The Turn 125 civ ranking list had me equal with the AI civs in tech (all of us had about 20 techs researched), which was a great sign since I was doing a deep tech beeline and skipping many cheap technologies. I didn't even have Bronze Working! When I realized that I wasn't going to be able to produce three Great Scientists in time for my tech path, I opted to go a different route:
Because Athens had marble and a lot of hill tiles, I opted to mine everything here and go for the Porcelain Tower. I actually don't think this is a good wonder, and not worth building most of the time. Still, I needed that third Great Scientist, and my planning hadn't done a good job of setting up my cities to produce one naturally. As it turned out, I missed out on the wonder by a single turn, Bismarck completing it when I had one turn remaining. Argh! Stupid Bismarck also had marble, and of course he only paid 60% of the cost in shields to build the thing. Ah well, not every plan succeeds. This would delay my entry to the Industrial Age by about ten turns.
Very little happened during these turns. I clicked the "Next Turn" button quite a lot. Mostly, I took advantage of Open Borders deals to explore the entirety of my continent, which is now a necessity since there are no map trades in Civ5. Here's where I stood on Turn 150:
I've been at seven cities for some time now, and my gold/beaker production has increased significantly over the past forty turns. I was down to the last two techs that I needed, Navigation and Scientific Theory, although they were very expensive Renassiance ones. Diplomatically, I was now allied with four city states: two maritime and two cultured ones. The city state behind Germany was maritime, which I happily befriended as soon as I found it. I also poured 1000 gold into Florence, because for this game in particular the extra culture would speed me along to my desired social policies.
In a nice break for me, no AI civ was running away with the game. This huge mountain range you see pictured above made it very difficult for the AI to expand, with no land passage to the east (Bucharest blocks the only tile) and a single tile passage at Brantford in the south. Somehow, the Iroquois had managed to get a settler up there to Akwesasme; otherwise, however, they hadn't done much in this area. Bismarck still only had a single city to his name. Yes, 150 turns into an Immortal game, one of the AIs was running a One City Challenge. Bismarck had never been at war, and he had room to expand. What in the world was he doing?!?
A little bit later Catherine went to war with Hiawatha, as the AIs always seem to do, because the AI is a complete sociopath in this game that can never exist peacefully with its neighbors. I didn't care though. My tech beeline was finally complete:
Here you can see my empire right on the cusp of entering the Industrial Age. I have a settler on standby, and two Great Scientists ready to knock out the techs I need. I would consider this to be a "normal" empire, similar to what someone playing the game in traditional fashion would have. This kind of setup is strictly inferior to a mass city spamming build, however, which I'm about to demonstrate. (I'm not playing things optimally here, due to my Order policy beeline; alpaca's Infinite Rome game shows that an early spam of cities produces superior results.) Here we go:
My Great Scientists claim Archaeology and Biology as the free techs. It should be clear from this picture why I wanted three Scientists, to avoid having to research the expensive Scientific Theory tech. And while it's a little hard to see here, I've literally skipped everything I don't need on the rest of the tech tree. My military remains in the stone age, and I can't even see iron! Although again, since I have access to horses and knights, I can still fight without any real difficulty. Seems like a mistake in design to put the horse units elsewhere on the tree.
With access to the Order tree, I immediately claim all four social policies on the center column. Order itself provides a 25% production boost when constructing buildings in all cities, which is a very big deal indeed! "Socialism" subtracts 10% off the cost of all building maintenance - good, not great. It would not be worthwhile if Socialism wasn't a pre-requisite for other stuff. The last two Order policies are the ones that are really good. "Planned Economy" provides -50% unhappiness from number of cities, although this is a confusing way to word what the policy actually does. To put it more simply, every city costs you 2 unhappiness. Planned Economy removes one of those unhappy faces, reducing the penalty to only one unhappy face. It does exactly the same thing for India, despite what the wording suggests, taking Indian cities from four unhappy faces to three. This is an extraordinarily powerful social policy for large empires, well worth getting if you can afford it. Finally, Communism provides +5 shields in every single city, again obviously awesome when spamming them all over the map. The other two Order policies are not particularly useful, and should probably be skipped. Also, notice how I have EXACTLY enough culture to purchase these four policies on the same turn that I entered the Industrial Age? That was dumb luck, not planning. Even I can't time things that well! I wouldn't put it past T-Hawk though...
The setup phase was over. Now the fun can begin.
