This cavernous swimming spot doubles as a home to the largest known colony of bats in Central Asia.

A fiery crater has been burning in the Karakum Desert since 1971.

This "tower of death" has acted as an observatory, a religious hub, and an executioner's lair.

Light still pours into the ruins of this ancient Islamic observatory.

The Avenue of Mausolea is a series of grand palatial tombs.

The notorious "Hanoi Hilton" where Vietnamese colonial subjects and later American POWs, including John McCain, were imprisoned.

Twice a day a speeding train passes only inches from the homes of this residential neighborhood.

A unique collection of Soviet military artifacts lies hidden away in a disused train, in the unrecognized Eastern European republic of Transnistria.

Seventy-five miles of limestone caves host more than a million bottles of wine beneath a sleepy Moldovan town.

This sign marks the entrance to a tiny proto-state within the small country of Moldova.

The largest wine cellar in the world is a 150-mile network of underground caves near the capital of Moldova.

At less than four inches in height, this iconic fictional character is the smallest public statue in all of Moldova.

This abandoned Soviet circus is slowly being restored to its Communist-era glory.

A forgotten remnant of the Soviet Union, Transnistria is an unrecognized country hidden behind a heavily militarized border between Moldova and Ukraine.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

This no man's land slicing through the island is strewn with abandoned relics of another time.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

Inat Kuća, or "House of Spite," is more than just an oddly named restaurant.

This historic cemetery was inaccessible for several years due to dozens of land mines.

Oriental bazaar in the heart of Sarajevo.

The place where World War I began.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

A war-torn Olympic relic is being overtaken by graffiti and nature.

Dozens of Soviet-era trains and carriages fill this outdoor museum.