This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.

The bar where "The Great Train Robbery" was planned was once a nexus of high society and low morals.

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

The largest greenhouse in the world is home to over one million types of plants.

A historic London cemetery now serves as a nature park incorporating gravestones & memorial statues.

400-year-old garden, restored to beauty.

A fantastic castle rumored to be the birthplace of King Arthur.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

The longest hedge maze in the world.

Famously misunderstood wonder of the ancient world

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

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

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

The rusting relics of Southampton's former luxurious flying boat industry.

This charming, narrow-gauge railway in the Thames Estuary is sometimes referred to as the "Train to Nowhere."

The last resting place of the famous Native American princess is marked by a haunting monument.

An incredibly well-preserved piece of ninth-century Viking poop.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

This subterranean necropolis holds three floors of antler-dug grave caves.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

Stone Age solar temple is aligned with the sun on each equinox and solstice.