Sears Tower, Chicago

Built in 1974, 110 stores, 442 meters.
To provide stability against high winds, architect Bruce Graham used a new form of tubular construction for Sears Tower. Two hundred sets of bundled tubes were laid into the bedrock. Then, 76,000 tons of prefabricated steel in 15-foot by 25-foot sections were put into place. Four derrick cranes moved higher with each floor to lift these steel “Christmas Trees� into position.
Located in Chicago, Illinois, The Sears Tower was constructed in 1974, and has been the world’s tallest building, overtaking the World Trade Center. Although, it is no longer the tallest building in the world, the Sears Tower is the 5th tallest and still has the world’s highest occupiable floors, highest elevator ride and the highest roof deck. The top of the tower is the highest point in Illinois. It is said that four states can be seen from the top of the tower.
This tower was designed by architect Bruce Graham and engineer Fazlur Khan in a “bundled tube� system with nine squares, sheathed in a dark tinted glass curtain wall. The building leans a few inches due to its asymmetrical design and this can be felt occasionally. The Sears Tower has a separate tourist entrance and attracts more 1.5 million tourists each year.