Five design teams have been selected to present their ideas for the Chicago O’Hare Airport Global Terminal and Global Concourse expansion. The designs are on display at an exhibition opened by Mayor Rahm Emanuel at the Chicago Architecture Center. Teams include Fentress-EXP-Brook-Garza, Foster Epstein Moreno, Studio ORD, SOM and Santiago Calatrava. Known as O’Hare 21, the project represents O’Hare’s first major overhaul in 25 years.