The medieval network of canals hidden underneath the city is opened to explorers each year.

This 19th century cyclorama acts like an analogue time machine to a different era.

Amidst medieval and baroque buildings, five human-sized gherkins stand tall.

In this town's main square resides a statue of none other than the 43rd President of the United States.

The ruins of this prominent glass factory yield hidden treasures buried among the jungle floor.

Myanmar's beautiful cemetery for Allied soldiers who perished during World War II.

These muddy eruptions are less deadly than actual volcanoes but also more holy.

The oldest teak bridge in the world is made from the remains of a royal palace.

Over 2,000 ancient temples dot the Myanmar landscape at the site of this famed archaeological site.

This golden temple is surrounded by hundreds of stone tablets that comprise the "world's largest book."

Remains of military submarines built in secret jungle factories by the Tamil guerrillas' naval wing.

This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

Named after a militant urban guerilla, this famous former squat is a graffiti-covered stronghold of leftist culture.

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

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This man-made mound monument was built out of soil from all across the Polish empire.

The unsettling remnants of a torn down movie set lies nearby the ruined location of the actual Płaszów Labor Camp.

"Holy Wisdom" overlooks the city that became its namesake.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.