Historic Railroad Trail
Location: Nevada, Las Vegas, Black Canyon Area
Easy (and dog friendly) hike through historic tunnels along a portion of the old Hoover Dam Railroad.
Tunnel Terrace Walk
Location: New Zealand, West Coast, Hokitika area
Awesome little loop through neat historic mining tunnels.
Chasm Creek Walkway
Location: New Zealand, West Coast, Mokihinui area
Short family friendly walk to a nice tunnel and a cool old bridge – added bonus of a train wreck just off the trail in the water.
Charming Creek Walkway
Location: New Zealand, West Coast, Mokihinui area
Great hike with mining relics, tunnels, a swing bridge, a waterfall, and more!
Cu Chi Tunnels ♦
Location: Vietnam, Southern
War memorial park at the home base of the Viet Cong Tet Offensive, where you can tour the tunnels and buildings used by the fighters
DMZ
Location: Vietnam, Central
Various military sites can be visited in the demilitarized zone (DMZ) including the Hien Lung Bridge and Vinh Moc Tunnels