The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

Catacombs turned marketplace.

Rebuilt remains of a temple to Roman god Mithras.

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

An unusual round church in London with a Templar past.

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

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

Famously misunderstood wonder of the ancient world

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

The world's largest collection of witchcraft regalia.

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

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

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

Eighty million natural history specimens call this gargantuan museum home.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

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

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This dramatic landscape hidden on the Isle of Skye looks as though you've stepped into the magical realm.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

These fantastically named natural pools look like something out of a Scottish myth.

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