Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

A perfect circle of 24 mysterious holes dates back to prehistoric times.

An abandoned water sports stadium that has become a haven for graffiti and decay.

St Bernard de Clairvaux Episcopal Church, better known as one of the oldest European buildings in the Western Hemisphere.

A gaudy painted elephant stands in memory of south Florida's fallen carnies.

America's only city hall with minarets took architectural cues from Ali Baba and the Forty Thieves.

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

This beautiful Miami garden was designed as a laboratory for tropical plants.

The behemoth beasts engaged in an epic battle is the second-tallest statue in the contiguous United States.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

A stately palace has been converted into the world's largest cannabis museum.

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

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

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.

A beautiful but toxic fountain of mercury.

This semi-secret storybook hedge maze is also the oldest garden in the city.