It is generally accepted by everyone that skyscrapers were discovered in Chicago, the third largest city in the U.S. For the construction of Sears Tower, 2400 workers worked for three years, the building was completed in 1973. Skeleton tower consists of new pipes that cross section of rectangular shape, forming the basis of a huge square of side 69 meters. Everything was made of concrete, sits on pillars filled with chunks of rock, they are set by the layer of earth rocks. The huge new pipes welded together exceed the height of 50 floors, then start building it sharpens. Intaltimea seven pipes to reach the 66-story, then five pipes at a height of 90 floors and only two pipes to the maximum height - these two pipes are placed in the last 20 floors. The building has a height of 441 meters, but two television antennas, overall height reaches 520 m. The steel used to construct the skeleton would have built 52,000 cars. The inner surface of the building is 420,000 square meters, equal to 57 football fields. 104 lifts in the building works fast, which by their location property divided into three zones. The building has 110 floors and a total weight exceeding 222,550 tonnes. Were used 3219 km of electrical cables and 69,200 km of telephone cable and the elevator reaches a speed of 488 meters per minute. Fire skeleton of the tower is covered with black aluminum tower with over 16,000 bronze-colored glass that cleans six to eight times annual automatic washing machine glass.