This tower is the oldest high-rise building in Chicago outside of downtown.

Formerly attached to a 3.3 million ft² office building, the largest commercial building in the world upon completion and the largest timber building ever built.

The metal framing attached to the back is decorative, not structural. It serves as a reminder of the enormous structure which used to be connected to the tower.

The tower was a landmark for travelers starting off on Route 66, the historic highway between Chicago and Los Angeles.

The structure is capable of supporting one of the greatest floor loads of any known building in Chicago since the floor below the observation deck held tanks containing 200,000 gallons of water.

Upon completion the building had the highest insurance and fireproofing rating of any structure of its type.

This is the original Willis Tower. In 1974 Sears Roebuck & Company moved from this complex into what was then the world's tallest building.