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

A whimsical village of unique treehouses resides in a Washington forest.

Twin Peaks' real life Double R Diner has been restored to its damn fine television look.

This long, dark tunnel is open to hikers, but those without lights are known to get confused even on the straight path.

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

Rustic natural hot springs in the deciduous rain forest.

A theme park made of glass, from the gleaming books on the shelves to the crystal fish in the mirror lake.

Known as the birthplace of Korean Buddhism, this temple features an ancient, five-story stone pagoda.

This human-made pond is part of a Korean palace complex first built in the 7th century.

A traditional village rooted in the Joseon Dynasty.

This former coal mine has been turned into a sprawling modern art complex.

A Korean village where times stands still.

Over 80,000 carved wood blocks make up one of the world's oldest intact Buddhist canons.

About as hidden as can be, this specialty coffee shop is wedged between multi-story buildings at the end of a dark, skinny alleyway in Seoul.

To enter the lower hall of this temple, you must first walk through a dragon.

The abandoned hospital whose elaborate ghost stories cover up the dirty truth - an uneventful sanitation issue and other mundane reasons for its demise.

Secret North Korean passage discovered below the world's most dangerous border.

A 32-acre fun park dedicated to all things cheese.

The 400-year-old remains of the samurai invasion of Korea.