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.
Onward and Upward
The "world's tallest" title passes regularly from skyscraper to skyscraper. This is one of the most competitive contests in construction. Architects and engineers heartily embrace the challenges of building higher, and corporations and cities are always attracted to the glory of towering over the competition. The current champ is the Petronas Towers in Malaysia (see sidebar in previous section).
By all accounts, the skyscraper race is far from over. There are more than 50 proposed buildings that would break the current record. Some of the more conservative structures are already in construction. But the more ambitious buildings in the group are only theoretical at this time. Are they possible? According to some engineering experts, the real limitation is money, not technology. Super tall buildings would require extremely sturdy materials and deep, fortified bases. Construction crews would need elaborate cranes and pumping systems to get materials and concrete up to the top levels. All told, putting one of these buildings up could easily cost tens of billions of dollars.
Additionally, there would be logistical problems with the elevators. To make the upper floors in a 200-story building easily accessible, you would need a large bank of elevators, which would take up a wide area in the center of the building. One easy solution to this problem is to arrange the elevators so they only go part way up the building. Passengers who want to go the top would take an elevator halfway, get off and then take another elevator the rest of the way.
Experts are divided about how high we can really go in the near future. Some say we could build a mile-high (5,280 ft, or 1,609 m) building with existing technology, while others say we would need to develop lighter, stronger materials, faster elevators and advanced sway dampers before these buildings were feasible. Speaking only hypothetically, most engineers won't impose an upper limit. Future technology advances could conceivably lead to sky-high cities, many experts say, housing a million people or more.
Whether we'll actually get there is another question. We might be compelled to build farther upward in the future, simply to conserve land. When you build upward, you can concentrate much more development into one area, instead of spreading out into untapped natural areas. Skyscraper cities would also be very convenient: More businesses can be clustered together in a city, reducing commuting time.
But the main force behind the skyscraper race might turn out to be basic vanity. Where monumental height once honored gods and kings, it now glorifies corporations and cities. These structures come from a very fundamental desire -- everybody wants to have the biggest building on the block. This drive has been a major factor in skyscraper development over the past 120 years, and it's a good bet it will continue to push buildings up in the centuries to come.
