Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

This tangled English forest looks like something right out of a fairytale.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

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

The world's largest collection of witchcraft regalia.

Banksy gives themself artistic license with this piece of London street art.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

The sign at the garden gate reads: "These Plants Can Kill."

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

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

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

The ruins of an ancient mansion sits in front of and underneath a contemporary art gallery.

The secular incarnation of a religious meditation.

The ghost town where the villagers refuse to leave.

A small island with shimmering pink sands, home to loggerhead turtles and rare plants.

Thousands of rusting train cars have been slowly falling apart on the edge of Greece's second largest city.

This remarkable cave was discovered after a shepherd watched bees enter and exit through a small fissure.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

According to myth, Zeus himself was hidden in this cave to escape being eaten by his dad.

A spectacular cave and a beguiling lake.

Monasteries on rock pillars, once accessible only by frayed ropes.

This chapel is the site of a yearly pilgrimage that originated during the Middle Ages.

This little-known national museum houses over 40,000 works of art from across the world.