One of the shortest streets in York has an especially odd name.

Indents in the pavement are all that remain from a grisly death machine in Paris.

This frog-themed restaurant was frequented by Picasso, Saint-Exupéry, and more.

The video game-themed street art first popped up in the French city.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

The history of radiation is on safe display at the foot of a radiation science laboratory.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

An unusual ode to the late Irish playwright, complete with a squiggly bust and coffin-shaped bench.

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

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

A mysterious pair of mice eating a piece of cheese is London's smallest public sculpture.

A clock designed to run with perfect accuracy for 10,000 years.

The largest of London's subterranean rivers and once a mad, bad center of London life.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

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

A quiet memorial to those who died saving others in the heart of the City of London.

Classic game cookery takes center stage at what's widely considered London's oldest restaurant.

This statue once earned the distinction as one of the "Three Major Disappointments of the World."

This otherwise ordinary close on the Royal Mile constituted the end of the world for Edinburgh’s poorest residents.

A sweet symbol marks the place where torturous executions were once carried out.

A book bound in the skin of an infamous criminal, along with countless other specimens.

This early version of the guillotine was used to execute the man responsible for its construction.