Chicago had the first skyscrapers.
http://en.wikipedia.org/wiki/Home_Insurance_Building
First they had to figure out how to give a building a separate steel frame and hang the walls on it. Before that they just built walls from the ground up, higher and higher till the ground floor walls had to be several feet thick to support the weight.
Then they needed lifts to be invented to get people to higher floors.
Then they needed revolving doors to be invented - otherwise the gusts of air from lifts would suck you into or out of the building.
There's lots of room in America, but not on (for instance) Manhattan, which is quite small. But the only ones there are at the southern tip and in the middle, where the ground is mostly solid rock.