The World Trade Center Transportation Hub is a transit and retail complex.
Designed by Spanish architect Santiago Calatrava, the Transportation Hub is composed of a train station with a large and open mezzanine.
Oculus resembles a bird being released from a child's hand. The roof was originally designed to mechanically open to increase light and ventilation to the enclosed space.
This mezzanine is connected to an aboveground head house structure, called the Oculus, located between 2 World Trade Center and 3 World Trade Center, as well as public concourses under the various towers in the World Trade Center complex