For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

The art studio of an early 20th-century painter, hidden amid the Great Smoky Mountains.

Urban explorers embraced America's now demolished first suburban mall, south of Chicago.

This former Indiana quarry has been transformed into a park and SCUBA site where divers can explore the drowned mining equipment.

This stunning gothic ruin was a casualty of the Indiana steel industry crash.

The longest navigable underground river in the United States is home to countless blind and albino animals.

A vision of beautiful Hindu architecture in the middle of the American South.

An underground magnet for ever-changing street art.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

The flower-shaped temple in Virginia aims to transcend the boundaries of the world’s religions.

A sculptor's dream castle turned fantastical ruin.

An eerily abandoned stone tower is all that remains of a demolished dam on Cape Fear River.