Home to the world's largest refracting telescope and the birthplace of modern astrophysics.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

Gladiators once walked this ancient, subterranean passage.

From here, the loch appears to take the shape of mainland Scotland.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

These ruins witnessed the final gathering of the failed Jacobite Rebellion.

This modern work of art was a refreshing addition to one of the oldest theatres in the city.

These strange piles of magnetized volcanic ash travel across the desert about 50 feet per year.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This massive library holds what was once the largest book collection in the world.

Sitting atop a rock on Michamvi Pingwe beach, this restaurant becomes its own island at high tide.

A cemetery in Barcelona's Poblenou district is home to this touching funerary statue, which depicts death in the form of a winged skeleton.

One of Antoni Gaudí’s earliest buildings, built between 1886 and 1890 for the industrialist Eusebi Güell.

Barcelona's only remaining tram system takes riders to the Tibidabo funicular.

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

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.

One of Europe's largest supercomputers is housed inside of a disused chapel.

A stately palace has been converted into the world's largest cannabis museum.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

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

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.