This means you can get tiles that have industrial-era productivity from the first turn. Not only they can make or break a new city, but in early game, when your civilization is struggling under Despotism caps on production, tiles with resources are allowed to exceed that cap. You can also use a chain of Transports to move a unit across any distance of water in a single turn. Your artillery only has one movement point? That won't stop you from using it to attack a city a dozen squares away. If you had enough Engineers, you could build a railroad across any distance of grassland or plains in a single turn, then use that railroad to transport units across the railroad (all in the same turn).
![civ 5 exploits civ 5 exploits](https://www.gamosaurus.com/wp-content/uploads/calendrier/2021/aout-2021/humankind/combats-guerre-humankind.jpg)
The original Civilization had the Pyramids wonder."Power Democracy" takes a bit of fine-tuning to pull off correctly, but it'll allow you to run away with the game if you manage it right. The only downside (a Senate that would veto war declarations and try to force your civilization to make peace during negotiations whenever possible) was negated by the fact that the AI was already suicidally aggressive anyway, and that the player could use spies and their ludicrous piles of money to subvert enemy cities even when not at war. The upshot of this was that a civilization with these two governments could effectively pour the vast majority of its taxes into luxuries and watch as all of their cities turned into economic powerhouses over a few turns, continuously pump out trade caravans, and use the absurd amounts of money they would soon have in order to rush build any and all units and improvements necessary.
![civ 5 exploits civ 5 exploits](http://assets.sbnation.com/assets/2834825/zulu.jpg)
Meanwhile, trade caravans could be built and sent to foreign cities for absolutely ludicrous one-time cash windfalls. While other governments simply gave resource gathering bonuses to cities with enough happy citizens, Republic and Democracy governments got those bonuses by default, and happiness allowed for instantaneous population growth instead.