This abandoned island off the Venetian coast has been a radical monastery, a political prison, and a secret Nazi base.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

In the past, Renaissance sex workers were encouraged to entice customers on this bridge.

An exclusive waiting room built for the royal family in the 1920s is hidden in Milan’s central station.

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

Europe's official "zero-level," the equator of elevation.

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

In 1977, an eccentric book lover formed a micronation for book lovers.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.

This 2,700-year-old woman is the jewel of the Maidstone Museum's Egyptian collection.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

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

The unexpectedly beloved remnants of a controversial thermal power plant.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

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 earliest buildings, built between 1886 and 1890 for the industrialist Eusebi Güell.

On the wall of this medieval square, a symbol of the Spanish Inquisition.

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

This fountain was designed to honor the man who helped bring water to Barcelona.

Possibly the oldest church in Barcelona, this basilica has its pagan and Christian mythologies all mixed up.

Saint Joseph was said to heal the deaf and blind, but it was a much smaller miracle that got him canonized.

This cafe offers a curated collection of treats and tipples made by monks and nuns.

Turntable anonymously received orphans, alms, and groceries.