The fairy tale castle of the "fairy-tale king."

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

This historic mansion was built as a symbol of love between a husband and wife.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

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

The ruins of this antebellum sugar plantation are the end result of a Seminole attack during the Florida Wars of 1836.

Disney's abandoned animal island is now an overgrown ruin that was almost the coolest attraction ever.

Disney World's very first waterpark is now an abandoned ruin being reclaimed by the swamp.

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

An abandoned castle owned and ignored by Masons carries a cursed history.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

The inspiration for H.P. Lovecraft's horror stories and Batman's Arkham Asylum is now a condominium complex.

Most-visited and most-photographed slot canyon in the American Southwest.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

Rippling sand dunes frozen in the Arizona rock.

A huge musical instrument played by the ocean.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Sleep snuggled in a sphere suspended atop the forest canopy of Vancouver Island.

Chicago's North Park Village was once the largest municipal sanatorium in the country.

A lush green oasis in the middle of Chicago.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

This historic hotel invented the chocolate brownie.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.