The topiary maze at the Habsburg hunting lodge.

An ancient Egyptian temple in the middle of Madrid, Spain.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

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.

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

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

The attic of a four-century-old canal house hides a clandestine church.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

This hidden green space is the city's second largest conservatory.

The pioneer of psychoanalysis spent the final year of his life here, still seeing patients on that famous couch.

A museum wholly devoted to juvenescence.

This one has sailed five times as far as Sir Francis Drake's famous ship.

This luxury shopping lane has been protected by its own tiny police force for over a century.

Artists and musicians now rule over this former rail station.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

Eighty million natural history specimens call this gargantuan museum home.

Catacombs turned marketplace.

A cluttered and astounding collection of antiquities and curiosities.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

Hear the quietest sound from across the dome.