The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

Blighted Irish field and the ruins of a 19th-century cottage on the edge of urban Manhattan.

One of the world's tallest Ferris wheels takes visitors high above Las Vegas in a spinning party room.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

The world's largest military aircraft cemetery.

Once America's longest-manned military fort, now an abandoned hulk.

Colorado's only true geyser is hidden within the San Juan National Forest.

True to its name, this bouncy walkway may be the world’s smallest suspension bridge.

The stones that traveled from Spain to eventually become a holy place for San Francisco's nature worshippers.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

At the tallest peak in Colorado, an electrifying mix of thin air, lightning, and rivalry.

A regular looking rock with an unbelievable history.

Deep scars on the earth left by the Ice Age.

This tiny patch of arid sand sits in one of the greenest states in the United States.

These abandoned grain silos and tunnels are an urban exploration dream.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

A gothic palace of endless stalagmites and pseudoscorpions waits within one of the world's most beautiful caves.

River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

The last slot car racing arcade in Brooklyn is keeping the dream of speedy little autos alive.

The restored and active Victorian-era final resting place of San Francisco.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

Beautiful natural falls where Satan once ruined a pot of beans.

This black shoreline is made up of exploded lava particles.