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

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

An small and easily overlooked archaeology museum chock full of Egyptian artifacts.

A plaque marks the underground site of one of London's "lost rivers."

This hidden rooftop garden in downtown London offers a quiet respite from a bustling city.

No one knows who created the statues or if they are arranged properly—let alone the artwork's real name.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

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

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

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

The rose garden in Regent's Park where Pongo and Perdita met for the first time in Disney's "101 Dalmatians."

Part museum, part piece of Arthurian-inspired history, this stately hall attracts King Arthur fans from miles away.

Collection dedicated to brands, packaging and advertising.

These medieval tunnels provided water to the city above through centuries of civil war and plague.

One of the most popular megalithic sites in Ireland stands as a humbler version of Stonehenge.

The majority of the museum's large collection is held in a storage space open to the public a few times a year.

A gallery specifically dedicated to the botanical illustrations of a remarkable traveling lady.

The oldest working mechanical clock in the world.

Besieged by war, this castle ruin has crumbled into a peaceful picnic spot.

Visit the WWII bunker where the British won the battle for the skies.

An octagonal folly tower overlooking the sea.

A quirky "castle" formerly belonging to a famous British inventor.

A proud bronze billy stands as an eternal symbol of Ireland's oldest festival, where a goat is made king.

Locals call it the "Give Peas a Chance" bridge because of its distinct graffiti.