Rome's semi-secret peephole vista is also a former Crusader stronghold.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

Once the home of a hermetic monk, this cave now houses a small church.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

An exquisite collection of fairytale conveyances that puts most car museums to shame.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

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

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

The largest collection of handbags in the world, the oldest of which were used to carry Bibles, primarily by men.

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

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

A beautifully eclectic mix of architectural styles.

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

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

The only surviving piece of Copenhagen's 16th-century defensive wall.

A collection of noses tucked inside an art museum reveals how times have changed.

Beneath Denmark's Højbro bridge, a bronze merman and his seven sons forever mourn for the mother and wife who left them for land.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.