The other side is actually green.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

A small peaceful park and waterfall tucked amid the urban grind of Midtown Manhattan.

Murals of the wild parties once held on the frozen River Thames.

The wooden telephone box tucked away in London's Piccadilly was the original prototype of the iconic kiosk.

Bronze sculpture celebrating the relationship between Churchill and Roosevelt.

A plaque marks the underground site of one of London's "lost rivers."

This massive Brazilian church is built like an angular, technicolor pyramid left by Mayans from the future.

A 125-meter long "tribute to the Brazilian people."

You feel like you're in a forest, but you're actually walking amidst the branches and trunks of a single giant tree.

One of the two original gateways into the Kasbah, this gateway is a nesting site for storks.

The Great Fire of London and the regulation of one-way streets both started in this alley.

The Cambridge pub where Francis Crick announced that he and James Watson had discovered the DNA double-helix.

Numberless clock creates a meal of time for the dreaded, insectile Chronophage.

This giant sculpture made of trash is a critique of society's wastefulness.

The Columbia Road Flower Market is now open every Sunday, rain or shine.

The ritual has been performed uninterrupted for nearly 700 years.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

A forgotten relic from New York's bygone trolley system hides in plain sight under a bridge.

This historic building housed the surviving crew members of the Titanic, who were left destitute after the wreck.

The most confusing clock in New York.

Rummage through this sunken ship, but leave your scuba gear at home.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

Mysterious 500-year-old tapestries depict a unicorn hunt.