A small etching on the white marble parapet was written in runic script by a Viking mercenary.

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

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

This historic Amsterdam bar used to accept sailor's monkeys as payment.

One of the world's tallest statues is also one of its most hated.

This unattributed sculpture in Amsterdam is hiding in plain sight.

A public urinal so pretty, it was declared a national monument.

A beautifully eclectic mix of architectural styles.

The former home of a mad diplomat is said to still be marked in bloody, arcane scrawls.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

The world’s narrowest house makes for an awkward, four-foot-wide living space.

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

A hidden art gallery in an abandoned Warsaw fort.

Monumental sculptures guard many of the graves, transforming this necropolis into an open-air fine art museum.

This abandoned Greek island was the last active leper colony in Europe.

A unique opportunity to stay the night in retrofitted sections of sewer pipe.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

This 19th century cyclorama acts like an analogue time machine to a different era.

The amazing wonder cabinets of a very rich Austrian archbishop.

Site of the 1889 murder-suicide of crown prince Rudolf and his lover Mary Vetsera.

A Parisian boutique devoted to la Sape, the elegant Congolese fashion subculture rooted in European colonization.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

Original cabaret handbills, posters, and feline artwork are a purrfect highlight of the Museum of Montmartre.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.