Each winter this underground cave forms a dazzling ice palace.

This extinct shield volcano is the lightning rod of the Cascades.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

This natural marble cave is one of only five national monuments in Oregon.

Robots, lasers, and whoopee cushions, oh my!

The highest point in Wisconsin is capped by two towers that are not as mythic as Tolkien's but provide much better views.

A bizarre house filled with an astounding array of collections.

One of the largest aviation events in the world brings half a million aircraft enthusiasts to Wisconsin each year.

One of the last surviving C-97s sits in a field in front of a Wisconsin inn.

This historic hydroelectric power plant in Japan has been preserved and is open to the public.

This faux-seedy Japanese arcade is made up to look like a maze of alleys straight out of a cyberpunk dystopia.

Started nearly 100 years ago, this science experiment just keeps on going, ever so slowly.

A miniature train-ride through Slovenia's largest cave system.

America's greatest forgotten garden and the former stomping grounds of Son of Sam.

Cabaret where the show girls are all androids, and the patrons couldn't be more pleased.

An open-air sewer system that was covered piece-by-piece over 300 years.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

An unsettling shrine dedicated to the ravenous beast that prowled 18th-century France.

A Gothic cathedral created from volcanic rocks.

Two hundred tons of pioneer artifacts were painstakingly recovered from a shipwreck at the bottom of the Missouri River.

World's smallest skyscraper, the product of a remarkable con.

Constructed thousands of years ago, these stone circles offer incredible insight into the lives of the people who built them.

The world's largest drain sits below the city of Kasukabe, Japan.

Elaborate series of tunnels where traces of mass suicide are still visible.