The different systems on the exterior of the building are painted different colors to distinguish their different roles. The structure and largest ventilation components were painted white, stairs and elevator structures were painted a silver gray, ventilation was painted blue, plumbing and fire control piping painted green, the electrical elements are yellow and orange, and the elevator motor rooms and shafts, or the elements that allow for movement throughout the building, are painted red. One of the “movement” elements that the center is most known for is the escalator (painted red on the bottom) on the west facade, a tube that zigzags up to the top of the building providing visitors with an astonishing view of the city of Paris.