Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

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

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

This cemetery features modernist statues as strange as its name.

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

A hidden treasure in London with a rich medieval history, and the resting place of many luminaries.

A historic house left in "dramatic still life."

A tongue-in-cheek arcade where the games are based on everyday life.

This South London cemetery holds the remains of more than 15,000 people.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A kaleidoscopic warehouse-maze of handmade neon signs.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

This beautiful Victorian ironwork masterpiece was built to keep London from smelling like poop.