Third Tunnel, dug by North Koreans to invade South Korea, near Panmunjom, Demilitarized Zone (DMZ), South Korea, Asia

Third Tunnel, dug by North Koreans to invade South Korea, near Panmunjom, Demilitarized Zone (DMZ), South Korea, Asia

Soviet-era nuclear bunker, central Tirana, Albania, Europe

A tourist walking through The Underground German Hospital in Guernsey, Channel Islands, United Kingdom, Europe

Mari man walking on tracks in mine

Guernsey Underground German Military Hospital from World War Two, Channel Islands, United Kingdom

Alcohol filled jars line the long corridor of Tunnel 88, a former military shelter now used to store locally produced wines and alcohols

Beihei Tunnel, the former military tunnel designed to house equipment and personel is now used as a tourist attraction with free boat rentals to tour the caves

The entrance to an old military tunnel, Tunnel 88 now acts as a storage area for large jars which contain locally distilled alcohol and spirits

A truck drives over a makeshift bridge supported by ruined tanks on the road north of the Salang Tunnel in Baghlan province, August 31, 2002. High in the mountains of the Hindu Kush, the road was destroyed several years ago by a flood from raging mountain rivers. The road was improved by the Soviets after their 1979 invasion of Afghanistan, and was a crucial link for troops and supplies coming from the Soviet Union. The mountain road is in terrible condition, and its repair is crucially important for the reconstruction of the country