Skyscrapers appeared in the late nineteenth century in the business districts of large American cities. Prior to that time, building height had been limited by the strength of the materials which bore the weight of the materials. As the height of the building increased, the thickness required grew which in turn diminished the useable space on the lower floors. A point of diminishing return was reached after a height of a few stories. The question of moving people and things to higher floors was another obstacle.

Two things changed the equation: the invention of the elevator and the development of metal framing, first iron and then steel. Limited elevators were developed in the first half of the nineteenth century, but did not become practical for passenger use in office buildings until later when improved safety was combined with better power, first steam and then electric.

The Monadnock Building in Chicago`s Loop was part of the first generation of skyscrapers. Work on the building began in 1889 and was completed in two phrases by 1893, at which time it was the largest office building in the world. The original south section was also the tallest building ever built with load-bearing masonry exterior wall. The north section used steel framing with light exterior walls.

Skyscrapers grew ever higher. The famed Flatiron Building in Manhattan was built in 1903 to a height of 285 feet (22 stories). The Metropolitan Life Tower in 1909 reached 700 feet and 50 floors, making it the tallest in the world until the Woolworth Building was completed in 1913 at 57 floors and 792 feet.

The Woolworth Building retained its title as world`s tallest until 1930, when the crown past to 40 Wall Street. That was capped by the Chrysler Building a month later and the Empire State Building the next year. After 1931, however, the decline in the economy during the Great Depression ended the competition for several decades. Only in 1973, with the opening of the World Trade Center, was a taller skyscraper completed.