Two Chicago landmarks: the Watertower and the Hancock tower. The old watertower and the pumping station across the street were the only buildings left standing after the 1871 Chicago fire.

The Hancock tower was the tallest building in the world upon it's completion. The engineer, Fazlur Kahn of Skidmore Owings Merril (SOM), had to pioneer several new design technologies to make the building possible. The large exterior structural cross braces are part of the architectural charm of the building. Legend has it that Kahn performed rudimentary motion experiments (to simulate how a person on the top floors might respond to the building sway) on a turntable at the Museum of Science and Industry on display to explain the inner workings of a washing machine.