The secret city built by the Manhattan Project.

Enormous lake at the bottom of a unique cave system.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Monasteries on rock pillars, once accessible only by frayed ropes.

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

Stunning wetlands ablaze with pink lotus flowers.

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

Giant pinnacles in the sun-scorched lands of Southern Utah have been nicknamed "white ghosts."

A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

This abandoned cemetery has a dark past of bodies buried over bodies.

The ruins of a cotton mill that was burned in the Civil War are still hidden in a Georgia forest.

Hikers can still stroll beneath the long conveyer of this abandoned mining facility hidden in a West Virginia river gorge.

Once connected to the outside world by a single train track, this ghost town is looked after by the National Park Service.

The only remnant of a small mining town is an abandoned railroad tunnel that is steeped in ghostly lore.

Crumbling Kennedys and a decaying Tecumseh are just some of the haunting remains of one man's cement art trail.

A ship that lived many lives under many names is now known merely as the "Ghost Ship."

The highest point in North Carolina and the United States east of the Mississippi River, Mount Mitchell is named after argumentative explorer Elisha Mitchell.