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

This ancient Irish tower could easily have stood in for Rapunzel's prison.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

This single room has survived the centuries with almost no deterioration.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The whimsical twist of this spire was either caused by the Devil, an unexpected virgin, or lead.

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.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

Northern Ireland's Brobdingnagian stepping stones.

The atmospheric road was never meant to be so creepy.

Elaborate tile work in this railway station tells the story of Portugal.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

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

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

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

This ancient theater was once the home of fierce gladiatorial battles.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

These gutted monastery ruins still stand proudly in the middle of the Italian countryside.

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

This massive subterranean fissure is known as the "underground Grand Canyon."

A cave in southern Italy adorned with thousand-year-old Biblical frescoes existed in obscurity until fairly recently.