Discovered by cows, these upstate New York show caves are presented with a healthy dose of psychedelic folk art.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

The longest continuous underwater road in North America was built at the insistence of Franklin Roosevelt.

Michael Jackson got Bad and Crocodile Dundee walked on heads in this iconic Brooklyn subway station.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Holding the most bodies of any cemetery in the United States.

A little lighthouse in New York City, surrounded by mysterious stories of insanity-driven construction.

The site of a tragic massacre that spawned a multimedia franchise.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

The drama of nature in full effect in this Nevada State Park.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

The largest island on the great salt lake is home to curious creatures and strange stories.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

A whimsical bridge adorned with decorative dragons.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

This replica of the Greek structure is in the heart of Nashville.

Why have you never heard of the second most popular tourist site in New York?

A spiritual vortex among the red rocks in Sedona.

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

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

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