The ghostly remains of an accidental sea.

These fantastically named natural pools look like something out of a Scottish myth.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

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

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Dramatic river bend surrounds a natural red-rocked pedestal.

The legendary building that needed ghostly approval before being built.

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

Medicinal spa created with the discharge from a geothermal energy plant.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

An emerald-green grotto just a short trip from Austin.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

A crumbling hospital from the 1850s on Roosevelt Island.

On the Oregon coast there is a natural hole that seems to be draining the sea.

World's first "penitentiary," meant to be humane, drove men insane.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.