360° views of the city plus five floors of optical illusions and hands-on science.

Dictionary Johnson’s favorite feline.

This former luxury resort in Kaua'i is now an abandoned relic.

Tiki luxury on Nob Hill.

When you can't get to the Pacific, just go to Florida.

An antique cemetery in New York, this land is home to any number of famed corpses.

The remains of a failed subway in upstate New York is now an underground graffiti bunker.

Eclectic architecture in the woods of New York.

A beautifully designed asylum was resurrected as a hotel and art center with a ghost story or two.

The "mysteries" of this quintessential roadside oddity were almost destroyed by neglect but were saved by fans of kitschy wonder.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

A site where “the ravages of the war are more striking…than any other place in contemporary Spain.”

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

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

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

One street divides a single town that stands in two U.S. states.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

This oversize piece of novelty cookware once cooked the largest pancake in the world.

A fountain standing as a testament to a doomed alliance.

A tiny church on a man-made island in the Adriatic.

The secret city built by the Manhattan Project.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.