A striking symbol of the Bulgarian capital.

The partially submerged ruins of a white marble quarry used in ancient Greece for over 1,200 years.

This ancient structure appears Roman, but was constructed during the 16th century and was utilized until 1911.

The second-largest Jewish temple in Bulgaria was deserted after World War II, seized by the communist government and then abandoned again.

Go surfing on this urban wave, "hacked" by local surfers.

A fearsome dragon clings to a corner of Munich's city hall.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

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

Half-hidden by grassy slopes, this striking Spanish colonial fort is now a museum of underwater archaeology.

At least seven hues of blue and turquoise make this freshwater lagoon unique.

Still standing despite its considerable slant, this tilted lighthouse has become a local symbol of resilience.

An ode to one of the dirtiest jobs during the construction of the Boulder Dam.

This megalithic tomb was crafted by a mysterious civilization that settled the island of Pantelleria.

Also known as the Blue Church, the building was consecrated to the daughter of Andrew II.

Launched by Napoleon's soldiers more than 200 years ago, a cannonball remains embedded in the tower wall.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

A restaurant and observation deck built in a unique broadcasting antenna.

A half-buried vehicle in Prague's is the latest iteration in a long-running piece by Czech artist David Černý.

Stroll past dozens of intricately-detailed scale replicas of buildings from all over Czechia.

In a city filled with Frank Gehry buildings, one stands out as one of the architect's weirder works.

Historic funicular railway, believed to be the shortest railroad in the world.

This serene oasis in an affluent Los Angeles neighborhood holds some of Gandhi's ashes and got Elvis into Eastern Philosophy.

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.