Columbia University in New York City has an extensive tunnel system underneath its Morningside Heights campus connecting many of its buildings, used by the university as conduits for steam, electricity, telecommunications, and other infrastructure. Throughout their history, the tunnels have also been used for other purposes, mostly centering around transportation. During the first half of the 20th century, they were used by students to avoid aboveground traffic. When the university housed the Manhattan Project, they were allegedly used to move radioactive material between buildings. During the Columbia University protests of 1968, students used the tunnels to facilitate their occupation of buildings on campus.
Throughout their history, the tunnels have been thoroughly explored by generations of students, and have been the subject of numerous campus legends. Though sections have been cordoned off by the university since the 1960s, either in response to the 1968 protests or rampant campus typewriter theft, many parts can still be legally accessed. Similar tunnels also exist under the affiliated Barnard College.
History
thumb|[[Enrico Fermi, John R. Dunning, and Dana P. Mitchell in front of the cyclotron in the basement of Pupin Hall]]
Columbia University's current Morningside Heights campus in Manhattan was dedicated in 1896. The oldest section predates the campus dedication; it was built when the land was owned by the Bloomingdale Insane Asylum, which used the tunnels to transport patients between buildings. In the section under Uris Hall and the Engineering Terrace, the deepest portion of the tunnels, running underground, furnaces and tracks still remain in the tunnels from when they were used to transport coal around the university for heating purposes. The largest sections of the tunnel system emanate from the university's power plant under the Sherman Fairchild Center.
According to student accounts, during the Manhattan Project, the tunnels were used by Columbia scientists to transport radioactive material between buildings.
In 1953, Columbia closed off the portion of 116th Street that bisected its campus. Prior to this, the tunnels were commonly used as pedestrian thoroughfares in order to avoid traffic, and were used by students well into the 1960s. During the Cold War, portions of the tunnels were used as nuclear shelters.
During the 1968 student strike, student staff at WKCR, Columbia's radio station, used the tunnels to break into telephone distribution panel rooms and seize the university's telephone system in order to allow reporters to communicate with station headquarters through campus phones. Though the tunnels helped students occupy many of the buildings on campus, they were also accessible to the agents of the administration; university staff and eventually the police used them to capture and remove the protestors, with the added benefit that they could do so away from press coverage. , many tunnels, including the one connecting the freshman dorms John Jay Hall, Wallach Hall, and Hartley Hall, are still accessible. , the tunnels under Barnard College, the university's affiliated women's liberal arts college, are still open for pedestrian use.