Tall buildings were first built in the mid-1850s, but they were not a popular building form until elevators came into common use. While New York City is known as the home of the skyscraper, they first flourished in Chicago following a devastating fire in 1871 that destroyed much of the city. Structurally, the skyscraper is a vertical cantilevered beam. In skyscrapers, a steel lattice-work skeleton replaces walls of concrete, brick, or wood found in shorter buildings.
Many forces are at work on tall buildings.
Gravity and the dead load of the tower push down, the ground pushes back up, and wind pushes at the sides. A foundation distributes the load into the surrounding ground material and can help balance the sideways wind force. The size of the foundation depends on the strength of the supporting ground. A foundation placed in rock can be smaller than a foundation placed in sand or mud.