How do you build a tunnel under Boston Harbor? Very carefully, of course. This remarkable digital archive from the University of Massachusetts-Boston brings together photographs that document the construction of the first Boston Harbor Tunnel, which was later renamed the Sumner Tunnel. This key part of Boston's infrastructure was constructed to handle automobile traffic from the North End of Boston to East Boston. The tunnel finally opened in 1935 and this collection contains over 70 photographs documenting construction and the properties that were demolished to build this impressive structure.