The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

Each year melting snow turns these Austrian hiking trails into scuba zones.

Fascinating town where normal life interfaces with the occult.

Colorful and chaotic stacked hotel in North Holland.

Hundreds of prehistoric stones, arranged in perfect lines in a French field.

Swiss vineyards in a UNESCO heritage site.

Gothic tower mentioned in Thomas Hardy poem "The Channel Firing."

The beams of the New College, Oxford dining hall come with an amazing story.

Twisted buildings adorn the banks of the Rhine river.

Famously misunderstood wonder of the ancient world

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

An ancient monastery, a locked room, and a mysterious book heist.

A Gothic cathedral created from volcanic rocks.

Children's hospital in London that operates on royalties received from Peter Pan, which J.M. Barrie signed over in 1929.

Bronze sculpture celebrating the relationship between Churchill and Roosevelt.

An unusual round church in London with a Templar past.

A 550-square-meter micro-nation off the coast of Britain.

The largest of London's subterranean rivers and once a mad, bad center of London life.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

A beautiful maze marks where three countries meet.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

This foolish Victorian sea fort was converted to a deluxe hotel.

Surreal riveted sea forts once protected the Kent shores from German attack.