19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

A hidden treasure in London with a rich medieval history, and the resting place of many luminaries.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

The London pub overlooks where the Mayflower was moored before setting sail for the New World.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

Hidden beneath the streets of London is a secret subway that only carried mail.

Eighty million natural history specimens call this gargantuan museum home.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Debatably clever, or just plain honest hotel advertised as "The Worst Hotel in the World."

A collection of 20th-century automata, penny arcade games, and musical contraptions.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.