A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

Dozens of Soviet-era trains and carriages fill this outdoor museum.

Once one of the largest rooms full of books in the world, this bookstore basement is still a treat for bibliophiles.

This library dates back to the late 17th century and was one of the first public lending libraries in England.

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

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The world's largest wooden structure.

Commonly acknowledged as the only public monument to the Devil himself.

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

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

This huge abandoned fortress hidden inside a mountain holds a world of subterranean secrets.

A statue of a boy looks up at where the famous rival to the Leaning Tower of Pisa once stood.

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 unexpectedly beloved remnants of a controversial thermal power plant.

Mountain where Jesus was first tempted by the Devil.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Construction of Barcelona’s iconic (but controversial) church was finally completed in 2026—a century after the death of its architect.

Memorials at a Florence railway station remember the citizens who were deported from Italy and sent to extermination camps.

A rotting air force base is now home to rare birds and scarce plants.

The oldest of the three remaining bridges in England with buildings on top of them.

Modern commuters still pass through this 2,000-year-old Roman archway.

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.