This abandoned prison castle has become an imposing gallery of graffiti art.

Curious cave that stays a cool 56 degrees all year long.

The iconic remains of the original Academic Hall that burned down in 1892.

Symbolic attempt to overcome the issues of life.

This open air cathedral invites all faiths to worship under the only roof big enough to fit them all: the sky.

Part of a worldwide art project, this mysterious semicircle of concrete shapes holds the pieces of a larger story.

This huge clock made of flowers and simple machinery was once used a political weapon.

One of few surviving standpipe water towers in the U.S.

This modern castle sat empty for decades before a fire inspired its builders to complete its luxury halls.

Unique tower has outlasted a takeover of the company.

A pharmacy built in the shape of a mortar and pestle, now resembles a fancy cocktail.

Elevated freight railway turned wildly successful urban park.

This tiny man looms large over downtown Charleston.

America's post-nuclear-attack chambers of Congress.

The oldest arched-covered bridge in Virginia has truly withstood the test of time.

Outdoor exhibits explore the contributions of European, African, and indigenous peoples to American frontier culture.

The oddly shaped, steam-spewing building is now an art studio and gallery.

A former mental hospital founded in the 1930s by a eugenicist who advocated for the forced sterilization of patients.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

A quintet of history museums make this Virginia graveyard as much a resting place for funereal history as it is for people.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

One man's extraordinary topiary garden in a small South Carolina town.

This titanic steel chain linking two buildings was installed without permission but instantly beloved.