https://www.grunge.com/193269/secret-tunnels-that-lead-to-strange-places/
LOS ANGELES HAD 11 MILES OF PARTY TUNNELS
THE U.S. ATTEMPTED TO BUILD SPY TUNNELS UNDER D.C.
THE KNIGHTS TEMPLAR HID THEIR SPOILS WITH SECRET TUNNELS
NOGALES, AZ IS AMERICA'S DRUG TUNNEL CAPITAL
PORTLAND'S TUNNELS MAY HAVE BEEN USED FOR KIDNAPPING
THE WALDORF-ASTORIA SITS ON TOP OF AN OLD SUBWAY TUNNEL
THERE'S A SECRET PASSAGE FULL OF ART IN FLORENCE