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.

Part modern art project, part traditional chapel, this see-through church is only substantial from the right angle.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

Ring the bell to enter a bar that looks equal parts museum and old curiosity shop.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

The world's oldest bookshop still in operation.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

Elaborate tile work in this railway station tells the story of Portugal.

After a night ravaged by bedbugs, it's said King John ordered the creation of this weathervane.

An ancient instrument used to measure the waters of the Nile so Egyptian farmers would know whether to expect famine or flood.

Charnel house at the foot of Mount Sinai.

An alien landscape of chalk-rock in the Egyptian desert.

This half-forgotten fortress was constructed by the Ottoman conqueror of Constantinople.

One of its engravings is believed to be among the first representations of medical and surgical instruments.