This snug medieval lane is one of the narrowest streets in the world.

The second largest in the world, this massive underground void has its own subway.

A beautiful but deteriorating monument of Soviet architecture.

Ruins of a former government building destroyed during the Georgian-Abkhaz war in the wake of the fall of the Soviet Union.

These limestone cliffs are associated with the Greek myth of Prometheus.

An abandoned mansion is now a haven for urban explorers.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

The world's first invisible city square is an homage to a man who pushed the boundaries of art.

Museum deep in the catacombs of St. Michael the Archangel Church is explored by touch, sound, and smell.

Legend has it that Napoleon Bonaparte fell in love with this Gothic church.

Plaques celebrating Lithuanian writers freckle a wall of this picture-perfect path.

Travelers who fall victim to this mermaid's charms are destined to stay in Užupis forever.

This micro-nation may be some sort of prank, but its constitution sure seems official.

Over time, this castle grew to encompass the entire island.

Dedicated to the lives lost during a fatal stampede in the Nyamiha Station.

A beautiful and moving memorial set on a little island in the middle of the river in Minsk.

Nearly three tons of weapons from the Vietnam War still remain in this small, hidden museum.

Witnesses claim the Virgin Mary statue outside the church once mysteriously shed a single tear.

Artifacts and memories from the Vietnam war, located in a place that experienced it first hand.

This French colonial post office is arguably the grandest in all of Southeast Asia.

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

This Vietnamese hell cave lets visitors take a walk through a devilish underworld full of demons.

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

A restaurant and observation deck built in a unique broadcasting antenna.