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

Who needs fancy modern water slides when this giant North Carolina rock works just as well?

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

These spooky and unusual stone formations create an underworldly landscape.

Acres of natural wonders left behind by a socialite-turned-gardener.

The final resting place of the great escape artist, where some still gather to wait for his escape from death.

More than five miles of underground passageways.

Railways may have forged this quintet of lovely tunnels, but now they are open to hikers.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

Amsterdam's Red Light District leaves little to the imagination.

A popular tourist cave with a dark past.

Named after a bandit and the star of several Hollywood prehistoric landscapes, these sandstone formations are a historical part of the Los Angeles natural landscape.

Where manatees are the snowbird vacationers in these balmy Florida springs.

The scuba diving training facility was named for the steam that rises from the cave's chimney.

This elegant arc of a waterfall marks a religious turning point.

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

This bright yellow relic is the final survivor of a short burst of seashell-shaped petrol pumps.

This lake in the Cascades lives up to its name, disappearing down a hole every spring.

A historic covered bridge, only one of two remaining in North Carolina.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

Ingenious bakery opens up the first Cupcake ATM at their flagship location in Beverly Hills.

Science fiction's grandfather has a fittingly marvelous tomb.