îIn the space of 60 years, between 1860 and 1920, the United States assumed the features of the modern country we know today. Technical progress boosted the development of this vast territory. The population increased more than threefold with the arrival of millions of immigrants. Vast cities were built, packed with skyscrapers. This previously divided republic had become a leading world power.╠@Skyscraper cities@
Tall office blocks, lit up by electricity, became the symbol of this progressive, efficient society. They fascinated foreigners, artists, poets, and even those who saw them every day.
