The little-known second castle that William the Conqueror built in York.

Follow the original medieval paths that wind through this intriguing section of the city.

Stonehenge has nothing on Castlerigg’s views.

This tree was grafted from the actual tree that led Isaac Newton to ponder the theory of gravity.

The Liverpool street made famous by the Beatles is real.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

Ireland's most remarkable collection of these curious cone-shaped houses is worth the buzz.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

An icon of the city, this chapel features an amazing dome ceiling and offers panoramic views.

This castle has links to Portugal’s founding and struggles for independence.

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

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Spain's largest bullring offers a unique glimpse at architecture and history.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Go surfing on this urban wave, "hacked" by local surfers.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

The summer residence of a Spanish ambassador who brought viticulture to an impoverished region, sparking its transformation into one of the world's best wine regions.

A whimsical bridge adorned with decorative dragons.

A miniature train-ride through Slovenia's largest cave system.

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

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

These medieval skyscrapers dominate the skyline of this small Tuscan town.