What was the original name of Chicago’s Willis Tower?

Chicago’s Willis Tower was originally called the Sears Tower.

The building was commissioned for Sears, Roebuck & Company, whose headquarters and employees occupied much of the tower after it opened in 1973. Its original name remained in common use for many years, even after Sears moved away. In 2009, the building officially adopted the name Willis Tower after the Willis Group became a major tenant.

Designed by Skidmore, Owings & Merrill, the tower uses a bundled-tube structural system developed by engineer Fazlur Rahman Khan. Its nine square tubes are grouped into a larger vertical composition, allowing the tower to withstand wind while keeping the floor plan practical.

Many Chicagoans and visitors still call it the Sears Tower, so both names appear in conversation and older publications. The official modern name is Willis Tower, but “Sears Tower” is the historically original name and remains one of the building’s best-known identifiers.