The new supplemental tower and associated base building for the North Airfield development of O’Hare International Airport is approximately 225 feet to the cab floor with a 400-square-foot cab and a 10,000-square-foot base building. The project used more than 200 tons of structural steel and 2,100 cubic yards of concrete. The lower core of the control tower has an architectural concrete finish, and the cab level of the tower is completely surrounded by glass. The glass sheets measure 19 feet long and weigh as much as 4,000 pounds. The project included an air-side construction site, construction height restrictions and strict coordination to meet FAA requirements.