An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

A house carved into a rock in the 1940s.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

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

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

One of few lasting examples of the brief octagon craze that developed into folly.

The giant pair of sexy legs sticking out the window of this costume store have become its main draw.

This private residence was the template for one of the most beloved television homes of all time.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

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

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

This stunning iron gate designed by Modernist architect Antoni Gaudí is filled with mythic symbolism.

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

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This cemetery features modernist statues as strange as its name.

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

According to a gruesome legend, an architect sacrificed his wife to build this spectacular, 16th-century cathedral.

Locals believe this abandoned ruin on the outskirts of Bucharest is haunted.

Romania's triumphal arch looks out over Bucharest.

A medieval church built up to defend its village.

Nine centuries-old fortresses guard the walls of this medieval Romanian city.