An abandoned Cambodian resort that mirrored the downfall of the country as it was happening.

This aquarium has almost as many world records as it does fish.

Ha Long Bay's "Cave of Surprises" houses a popular phallic rock formation.

Submerged trees jut ghost-like out of an idyllic turquoise mountain lake.

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

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

Hidden deep in the Guatemalan jungle is a turquoise paradise of natural pools, caves, and waterfalls.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

The abandoned Japanese amusement park once loomed as a dystopian Disneyland.

A fifth-century temple improbably built into the side of a cliff.

The original "capsule building" is a masterpiece of Metabolist architecture.

Siberian ghost town built by gulag prisoners.

One of the world's largest ice festivals dazzles visitors for over a month with radiant sculptures and carvings.

Rivers of cattle blood gone, a strange Escheresque building remains, the last of its kind.

This iconic Russian space museum sits on a landmark space production facility and houses the Vostok 1, the first manned spacecraft, that was also built here.

A long abandoned hospital building on the outskirts of NYC.

This former textile district now is now a thriving center for contemporary Chinese art.

Secret Soviet city once home to Russian cosmonauts and space training facilities.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

The villagers of the coldest inhabited place on Earth adjust to unique challenges presented by day-to-day living.

The world's second-largest excavated hole.

The final resting place of a space program monolith.

A building so large that it has its own weather.

Beijing's expansive subterranean hiding spot now crumbles away as a tourist destination.