Tucked between a side street and a theater, this arch once led to a prestigious riding school, and now opens to a courtyard and community garden.

First road tunnel in England.

Legend has it that seven Anglo-Saxon kings were coronated on this stone, located in the appropriately-named town of Kingston.

One of Jeff Koons’s largest sculptures and his first commemorative work.

A domino effect created with Britain’s iconic telephone boxes.

One of the largest objects salvaged from the famous sunken passenger ship.

On the outside of the Mersey Tunnels, an Art Deco sculpture of an Egyptian Pharaoh wears goggles and racing gear.

A plinth outside a church displays sculptures by local artists.

A tribute to an 18th-century British surveyor.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

For more than a century, revolutionary graffiti has marked the wall of a Parisian church.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

The location of this small park was once the site of an infamous public morgue.

This demon atop the Notre-Dame de Paris looks utterly bored.

BDSM, 1930s Style.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

This innocuous-seeming building is actually the remnant of a major wartime brothel.

This renovated Art Nouveau bathroom from 1905 is worth the price of admission.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

This small, ingenious cannon once helped regulate Parisian life.

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

This massive library holds what was once the largest book collection in the world.

A 400-year-old church covered floor to ceiling in ex-voto offerings from the faithful.