Psychedelic murals coat the inside of a nondescript research library.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

The Andean town where every single building is decorated with a brightly colored frieze.

Enchanting cave with a river crashing through the roof.

A dangling church built over a Colombian gorge.

This picturesque mansion has gone from opulent ruin to nature museum.

An explosion of natural color known as "the river that ran away from paradise."

This feline raises a friendly paw at drivers barreling toward the freeway.

The romantic botanic tunnel feels like a well-kept secret.

This weird abode has inspired everything from the "House On Haunted Hil" to a robot hunter's pad.

The famed architect designed this Minnesota gas station of the future with a lookout tower.

The U.S. Fish Commission’s effort to mass produce carp.

Built by the patriotic residents of Boonsboro in a single day.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Where animatronic singing fish go to retire.

This collection of French root art looks like an indoor fairy wonderland.

A museum in England’s Lake District dedicated to the trusty pencil wants you to know the story of their World War II spy pencils.

A cabin completely covered in coffee mugs, where visitors are welcome to leave one of their own—if they can find an empty nail.

"The Hoppiest Place in the World" holds the world’s largest collection of bunny memorabilia and is a singular testament of a couple's devotion to all things Leporidae.

The largest collection of ornamental hair combs on the planet.

This museum glorifies the humble potato.

Cat art as far as the eye can see.

A son's promise to his dying father in the form of a covered bridge filled with thousands of seashells.