This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

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.

The most loyal of little dogs, or a Victorian era publicity stunt?

Protecting the dead from opportunistic body snatchers.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

A 18th century graveyard and its astonishing cortege of macabre iconography.

A strange rock with a sinister reputation lurks within the crimson waters of this Scottish glen.

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

The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

This network of narrow, medieval passages has the most delightful name.

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

Although it appears ancient and mysterious, the quirky folly was actually built 200 years ago by an eccentric estate owner.

A century-old tradition has culminated in a small but singular collection of feline effigies.

This memorial to World War II's fallen airmen shows us the movements of the stars that once guided them.

One of the shortest streets in York has an especially odd name.

Cycle the solar system—from the sun to Pluto—right here on earth.

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

Astonishing rock formations dot the Brimham Moor landscape.

This witch statue remembers a time in England's history when fear trumped truth.

Once thought to be the mysterious work of a witchy prophetess, a well with unusual properties turns objects into "stone".

A 600-year-old mini shrine guarded by a sword-wielding knight hides in a crumbling cliff face.