Soaring at 1,450 feet, Willis Tower (formally Sears Tower) is one of the world's tallest buildings. When you include the twin antenna towers, the building's height is at 1,730 feet. In fact, it owned the title of world's tallest building from the time it was built in 1974 until 1996. Malaysia's Kuala Lumpur has disputed that honor, but still, if you only count height in terms of highest roof, highest occupied floor and highest antenna, Sears Tower is still the tallest building in the face of the earth. This is a must-see when in Chicago, as it affords a jaw-popping view of the city, with a thrilling elevator ride to the top as a bonus.

This building was designed by architect Bruce Graham and engineer Fazlur Khan. Its elegant exteriors are covered with stainless aluminum and glass. Located at 233 South Wacker Drie, Chicago, this is undoubtedly one of the city's top landmarks. It really is a triumph of engineering, imagination and ingenuity. The building is built with 114 rock chambers for support. It took 3 years to finish, with more than 16,000 bronze-tinted windows, miles and miles of electric cable and a floor space spanning four and a half million gross square feet. The building also spans two city blocks. The entire cost of the project is in the upwards of $150 million. This was designed for the biggest retailer of its time, Sears, Roebuck & Company.

Every day, lines of tourists wrap the building as they line up to enjoy the attractions that Sears Tower has to offer. First off, there is the Skydeck, which is 1,353 feet above the ground. It is the highest and most visited observatory in Chicago. Being in the Skydeck is even more exciting when the wind blows, as the building, on the average, can sway at approximately 6 inches from the center.

Aside from the awesome view, the Skydeck also features interactive displays of popular Chicago residents both past and present – the city's dreamers, sports stars, musicians and architects. The interactive exhibits also feature multi-language kiosks so that those speaking only French, German, Spanish, Polish and Japanese can also make the most of the tour. For children, Chicago stoops down to their level with Knee High Chicago. This four-foot high exhibit is a walk-through of the city's history and sports.

Other attractions include its elevators, which can go up and down for as fast as 1,600 feet a minute. The 70-second elevator ride will take you to the 103rd floor observatory post-haste. From this lofty vantage point, you can see Michigan, Indiana, Wisconsin and Illinois on a clear day. This means a visibility of up to 50 miles. The tower has 106 elevators (both single and double decker types). These have 50-inch flat screen monitors that show the earth as seen from the Space Shuttle Endeavor. Also, at the ground floor lobby, there is "the Universe" a mobile sculpture by Calder.

A word of warning, though. A tour of the Sears Tower is not for those who hate heights or crowds. You should set aside at least an hour for this trip.

The Tower was recently purchased by the London-based insurance broker illis Group Holdings, Ltd. and officially renamed on July 16th 2009.

There is a "It's the Sears Tower" petition going on for Chicago's people to express their wish to maintain the historic name of Sears tower.