The curious underground history of keeping Paris clean.

Stroll through retro Paris while shopping for old postcards and discarded doll heads.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

A small but immensely extravagant palace built by the "Night King."

Hundreds of bras, blowing in the wind.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

This massive subterranean fissure is known as the "underground Grand Canyon."

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

Home to 10,000 medical specimens including the remains of Rudolf Virchow's extensive collection of pathological specimens.