Rebuilt remains of a temple to Roman god Mithras.

The curios of pharmacist and collector Henry Wellcome.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

A hands-off space for graffiti artists to hone and display their skills.

360° views of the city plus five floors of optical illusions and hands-on science.

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

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

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

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

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

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