The Columbia campus is normally open to the public via the entrances
on Broadway and on Amsterdam Avenue at West 116th Street. When Columbia
took over this land in the 1890s, it was with the agreement that 116th
Street would remain a public street, and it did for a few decades, complete
with automobile traffic. At some point it was closed to cars but remained
open to pedestrians. But when the buildings were occupied, Columbia ID was
required to enter.