Map showing all locations mentioned on Wikipedia article:
The
Cape Cod Canal Tunnel is a ficticious tunnel under
the Cape Cod
Canal. It has been popularized by the selling of
faux bumper sticker permits, usually with a red number 17 in the
center. It
has also been used by locals trying to mess with tourists,
directing them to a nonexistent entrance near the Massachusetts
Military Reservation.The other entrance of the tunnel is purported
to exist in New
Bedford.