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

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

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

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

The first island in the world designated a light-pollution-free astronomical observation point.

Underground hospital complex constructed by slave laborers during the German occupation of the Channel Islands.

A 150-year-old steam locomotive crosses the southern half of the island daily.

World's largest working waterwheel has been around for over 150 years.

This hidden bridge is where local children leave gifts and messages for the island's fay folk.

Underneath a chalk hill in France lies what Hitler hoped would be the underground launching base for a devastating new weapon.

Hundreds of prehistoric stones, arranged in perfect lines in a French field.

This bridge was constructed from the rubble of the infamous Bastille.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

One of the highest mountain passes in Europe has been ranked among the best driving roads in the world.

This breathtaking monastery was established by Saint Benedict himself 1,500 years ago.

Erotic art covers the walls of the largest ancient pleasure palace.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

The glowing blue Nymphaeum of Emperor Tiberius.

Pompeii's less famous neighbor is still revealing her secrets.

A crumbling bakery where forced laborers from the nearby concentration camp toiled to feed their fellow prisoners and Nazi soldiers.

A museum that chronicles the history of the Nuremberg Trials for Nazi war criminals in the building where the trials were once held.

Several of these strange cone-shaped bunkers can still be seen around the former Nazi headquarters.

A statue of Vladimir Illyich Lenin guards this abandoned building in the "Forbidden City."

This former Soviet military base has over 10 original aircraft and an enormous amount of memorabilia on display.