Super Tall Skyscrapers - The Sears Tower

The Sears Tower is a supertall skyscraper in Chicago, Illinois, and the tallest building in the United States since 1973. By the measurement from the ground to the top of the antenna/spire it is the tallest building in the world.

There are four main categories in which the world's tallest building can be measured:

1. Height to the structural or architectural top (including spires and pinnacles, but not antennas, masts or flagpoles)

2. Height to the highest occupied floor

3. Height to the top of the roof

4. Height to the top of antenna

The height is measured from the pavement level of the main entrance. At the time, the Sears Tower held first place in the second, third and fourth categories.

Moreover, it is also taller than the Petronas Twin Towers, Malaysia when considering either the height to roof, or the height to pinnacle point. By either of these measures, the Sears Tower was only surpassed by the Taipei 101 in 2004.

Construction commenced in August 1970 and the building reached its originally anticipated maximum height on May 3, 1973. When completed, the Sears Tower had overtaken the roof of the World Trade Center in New York City as the world's tallest building. The tower has 108 stories as counted by standard methods. The distance to the roof is 442 m (1,450 ft 7 in), measured from the east entrance.

In February 1982, two television antennas were added to the structure, increasing its total height to 520 m (1,707 ft). The western antenna was later extended to 527 m (1,729 ft) on June 5, 2000 to improve reception of local NBC station WMAQ-TV.

The Sears Tower has the second most total floor space of any building in the United States, only behind The Pentagon.