Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

Thousands of pieces of art have been carved into the rock at the site of an ancient volcanic eruption.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

The world's only teal arches exist in a city that cares more about its aesthetic than an Instagram influencer.

A geological mystery on Camelback Mountain.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

See massive fossils that are over 200 million years old in northeastern Arizona.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

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

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

Once a lonely sentinel on the edge of the Great Plains, this rebuilt trading fort offers a glimpse of life on the Santa Fe Trail.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

A Circus legend leaves an unexpected endowment.

This glass-stain Mary attracted thousands of pilgrims until her head was shattered by a vandal with a slingshot.

The first custom-designed building to showcase the works of Dale Chihuly is a wonderland of glass and light.

A luxuriant botanical garden below sea level.

Florida might be at its most surreal in this museum devoted to the famed Spanish artist.

One of corporate America's best-kept secrets is also one of the most publicly displayed.

Georgia's highest point was given its strange name thanks to a simple translation error.

A museum and doll store featuring a surreal and super sanitized version of where babies come from.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

It's good luck to be mocked by this monkey.

Berlin's old airport.