Vertical Variations

As we've seen in the previous sections, skyscrapers come in all shapes and sizes. The steel skeleton concept makes for an extremely flexible structure. The columns and girders are something like giant pieces in an erector set. The only real limit is the imagination of the architects and engineers who put the pieces together.

Photo courtesy Wayne Lorentz: Glass, Steel & Stone The distinctive chrome-nickel-steel crown of the 1,046-foot (319-meter) Chrysler Building is a classic example of art deco architecture.

The earliest skyscrapers, built in the late 1800s, were very basic boxes with simple stone and glass curtain walls. To the architects who built these skyscrapers, the extreme height was impressive enough. In the period around 1900, the aesthetic began to change. Buildings got taller, and architects added more extravagant gothic elements, hiding the boxy steel structure underneath.

The art deco movement of the 1920s, '30s and '40s extended this approach, creating buildings that stood as true works of art. Some of the most famous skyscrapers, including the Empire State Building and the Chrysler Building (above), came out of this era. Things shifted again in the 1950s, when international style began to take hold. Like the earliest skyscrapers, these buildings had little or no ornamentation. They were made mostly with glass, steel and concrete.

Photo courtesy Wayne Lorentz: Glass, Steel & Stone The 738-foot (225-meter) Chase Tower in Dallas is a good example of the innovative design of the 1980s.

Since the 1960s, many architects have taken the skyscraper to new and unexpected places. One of the most interesting variations has been the combination of several vertical skeleton sections -- or tubes -- into one building. The Sears Tower in Chicago, the most famous example of this approach, consists of nine aligned tubes that reach to different heights. This gives the building an interesting staggered appearance.

The Tallest Tower Ever since the first towering skyscrapers at the end of the 1800s, cities and corporations have been competing to build the world's tallest. Right now, there is some debate over who holds the record. Not everybody agrees on which structures should be considered. Traditionally, the architectural community defines a building as an enclosed structure built primarily for occupancy. This excludes a lot of extremely tall freestanding structures, such as Toronto's 1,815-foot (ft) CN Tower, from the running. Even within "traditional buildings," there has been controversy. For example, if you include rooftop antennas in the total height measure, the Sears Tower stands 1,730 feet tall. Without the antenna, it's only 1,450 feet tall. But, conventionally, decorative structures count toward height, but antennas do not. So who currently has the lead? That honor goes to Taipei 101 in Taipei, Taiwan. Although it has nine fewer stories than the Sears Tower -- Taipei 101 has 101 stories and the Sears Tower boasts 110 floors -- Taipei 101 is taller. It stands at an amazing 1,670 feet -- that's 220 feet taller than the Sears Tower and 187 feet taller than the previous winner, the Petronas Towers.