Longest fortress system anywhere in Europe.

A musical instrument played by the sea.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

Mountain where Jesus was first tempted by the Devil.

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

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.

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

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

An overlooked memorial honoring the local Washington residents who died in World War I.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

Obscure Freemasons still live in D.C.’s largest private residence.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

Perhaps the most scandalous statue of America's first president.