The stately remains of Llywelyn the Great's mighty fortress.

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

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

This spectacular bridge supported by two gigantic hands looks like something out of a fantasy universe.

The convergence of two currents makes this a surprisingly pleasant getaway in the Arctic Circle.

This legendary city has been a tourist attraction for centuries.

The ruins of an 11th-century Norman castle with a rare, perfectly circular shape.

This automated sculpture of two men peeing will spell out text messages with their micturition.

A canvas of crops grow from vibrant red soil in this terraced farmland.

A Japanese cat island also populated by the descendants of a band of banished samurai.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This surreal statue brings a famous French novel about a supernatural cad to arresting life.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

The famous artist couple lived and worked here, in two different houses separated by a bridge.

Vortex-shaped aquarium hosts Europe's largest school of piranhas and other ocean creatures.

This gracefully curving formation looks like a massive wave that was suddenly turned to stone.

This one-time health resort was used by aristocrats around the world.

A scattered trail of street art adds a pop of color to the city's stark structures.

This "preacher's pulpit" once used for pagan ritual, is home to a new, and dangerous ritual.

This replica Viking village was created for a film that was never shot and is now open to visitors.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.