The longest escalator in the Western Hemisphere takes over three minutes to ride down.

The world's longest known cave system.

This subterranean disco dance club in a Cuban cave comes with bright lights and a dark legend.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

Submerged busts of communist and socialist figures from the USSR.

Nature took her revenge on the "Wickedest City in the World."

A small Portuguese cottage formed between boulders in the countryside.

A submerged village appears when dam levels drop.

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

No one is quite sure of the origins of these idyllic natural hot springs at an abandoned mountain resort.

Collection of trolley cars in the woods represent one man's attempt to preserve transportation history.

Shoreline strewn with the remains of ghostly fallen trees.

Former farm staffed by mental patients is now a public park.

Tour the original street level of Port Angeles, buried underground in 1914.

An obscure waterfall that looks like something out of a fantasy novel.

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

A walk through the historic city center, under the streets of Seattle.

An eerie, derelict amusement park in Berlin.

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

Grandpa Rainbow felt the neighborhood needed some color, so he picked up a paintbrush and went to work.

Eons old volcanic activity created one of the most stunning rock formations in the United States.

Micro-nation based around a nine-story high illegally built tower.

Moss and stone turn this waterfall into an otherworldly liquid veil.

Artist Danielle Jacqui decorates nearly every inch of her home inside and out with her work.