The Willis Tower (formerly the Sears Tower), the world's largest building from 1973 to 2004. The tower's innovative bundled tube structure was designed by Bruce Graham and Fazlur Khan.
Photo credit: Soakologist
The Willis Tower (formerly the Sears Tower), the world's largest building from 1973 to 2004. The tower's innovative bundled tube structure was designed by Bruce Graham and Fazlur Khan.
Photo credit: Soakologist