Hundreds of hidden passageways weave through the old quarters of Lyon.

Home to Alan Turing, the cracking of the Enigma code, and Captain Ridley's shooting party.

The bombed out remains of the old church were kept intact next to the new one, as a reminder of the futility of war.

London's only public statue of the much-married monarch adorns the gate to St Bartholomew’s Hospital.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

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

A plaque hangs near the execution place of the Scottish Independence leader famously depicted in "Braveheart."

The Metropolitan Police refurbished the blue box (perhaps not coincidentally) the same year "Doctor Who" returned to TV screens.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

Giant, friendly pelicans in Central London, the most unlikely of places.

Hear the quietest sound from across the dome.

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

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

Northern Ireland's Brobdingnagian stepping stones.

One of the few surviving street funiculars in the world.

A harem-inspired Moorish fantasy design in a Victorian-era Welsh castle.

Recently restored menagerie of Victorian-era beasts.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This gnarled old tree supposedly sprouted from seeds kept in the pocket of a 16th-century Spanish sailor.

The ship built to ferry passengers and goods to the doomed Titanic is now the last remaining White Star Line vessel.

A museum marks and documents the site of the Titanic's launch.