Grotto replete with mystical designs laid out in glued shell mosaics.

This charming railway is one of the oldest and steepest funiculars in England.

Used as an example in one of the first dictionary entries for "museum" in 1706.

A labyrinthine underworld of tunnels and caverns hides beneath the city.

The pretty iron lamp is a reminder of the architecture underneath London's streets.

The biggest and deepest Cold War bunker open to the public can be found in southeast England.

You can spend the night in Dr. Frank-N-Furter's castle.

After years of slow decline, a derelict Gothic castle is now being restored to life.

Giant naked man on a hillside.

The nearly 200-year-old folly has a secret spiral staircase hidden in one of its pillars.

A remarkable medieval structure born from a 14th-century disaster.

This skewed English house has looked like it's going to fall over for centuries.

Man-made cave with enigmatic carvings, some say made by the Knights Templar themselves.

This strange moor has a song written about it, Bronze Age carvings, and an alien sighting.

A petite castle folly in the English countryside.

This stately monument has been wearing a traffic cone hat for decades much to the delight of the locals.

Ancient Egyptian wigs, South American feather headdresses, a bounty of anthropological artifacts in Oxford.

This giant wooden treehouse within a sprawling garden has its own eatery.

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

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

A succession of eerily contemplative iron figures lead from a Scottish museum to the sea.

This magical museum celebrates the life and work of a seminal children's book writer (and occasional spy).

A beautiful ruin of a 14th-century Plantagenet castle built by a medieval mercenary.

Human-made caves excavated to hide a secret society of wealthy pagans.