Willis Tower, United States

Willis Tower is commonly known as Sears Tower.it is the tallest building in the United States and the seventh tallest Freestanding structure in the world.(source)

Building Name- Willis Tower
Building Type- Office, observation, communication
Location- United States
Construction Started- 1970
Constraction Finished- 1973
Architectural- 442.1 m (1,450 ft)
Tip- 527 m (1,729 ft)
Top floor- 412.7 m (1,354 ft)
No of Floors- 108
Mo of Lifts- 104 (With 16 double-decker elevators)
Architect- Skidmore, Owings and Merrill