The Sears Tower rises on a Muslim engineer's design

Bangladeshi-American engineer Fazlur Rahman Khan's bundled-tube system makes the Sears (now Willis) Tower the world's tallest building, a title it holds for 25 years. His earlier trussed tube shaped Chicago's John Hancock Center.

Khan's tubular structural systems remain the basis of modern skyscraper design; he has been called the greatest structural engineer of the twentieth century.