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

Scattered throughout London are ancient remnants of the city's former bounding wall.

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

Catacombs turned marketplace.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

The curios of pharmacist and collector Henry Wellcome.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

A 400-foot-tall tall map of Chicago makes this once-ignored building stand out.

One of the few remaining relics of the meatpacking hub that made Chicago the "hog butcher to the world."

Once at the center of U.S. finance, the historic Trading Room was meticulously recreated piece by piece and rebuilt in the Art Institute.

Illegal drag racing two stories beneath Chicago’s streets.

Not to be confused with the iconic New York City skyscraper, this Chicago building is a vibrant hub for artists.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

This historic hotel invented the chocolate brownie.

A century-old hotspot for jazz, frequented by everyone from Charlie Chaplin to Al Capone.

A science teacher's dream.

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.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

Paris' linguistic guide to the international language of, yes, love.