World's Most Extreme: Tunnels - National Geographic Channel (In Tamil)

Courtesy: National Geographic Channel (In Tamil)

List Of Top 10 World's Most Extreme Tunnels.

Moscow's Leforttovo Tunnel also called as "The Tunnel Of Death", New York's 2nd Avenue Subway Tunnel, Vietnam's War Tunnels, USA's Nuclear Missile Silo "Safest Tunnel", China's Bund Tunnel "Weirdest Tunnel",
Guoliang Tunnel "Riskiest Tunnel", Afghanistan's Salang Pass Tunnel "Roughest Tunnel", Swiss Alps Gotthard Tunnel Network "Largest Tunnel", Japan's "Mightiest Tunnel, Underground Temple", Mexican's Infamous Drug Tunnels "Most Criminal Tunnel".