The ruins of an ancient stadium that hosted gripping chariot and horse races.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

Stunning Roman aqueduct used for 1900 years and still standing.

A beautiful but toxic fountain of mercury.

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.

The monument is inscribed, "To Sagamore John and those Mystic Indians Whose Bones Lie Here”.

Dedicated to "the father of U.S. life insurance."

The world's second-largest sundial, made entirely out of stone.

The 953 windows undoubtedly make this the world's most beautiful screened porch.

More than half of this Indian palace is drowned but it looks all the more spectacular for it.

This abandoned stepwell is one of the largest, deepest, and certainly one of the creepiest in India.

This opulent 16th-century Maharaja’s palace is a unique mix of Hindu and Muslim designs.

Time has stopped at the house where Gandhi died.

An ancient iron pillar in Delhi that seems to be rustproof.

Nestled among the artifacts of the National Crafts Museum, this hidden gem offers hard-to-find regional foods from all over India.

A blooming house of worship for the masses.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

The ancient tomb acts as a calendar that keeps perfect time.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

An Iron Age fort on the edge of a seaside cliff offers a glimpse into an ancient, mystical world.

Achill's most recently abandoned village dates back to to the Age of Enlightenment.