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

Pop culture has helped to keep this iconic British building from being destroyed.

This hidden green space is the city's second largest conservatory.

The curios of pharmacist and collector Henry Wellcome.

Banksy gives themself artistic license with this piece of London street art.

A somber memorial honors the hundreds of thousands of lives lost at this labor and extermination camp.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Jesus' footprints and the first catacombs in the world.

Architectural monsters are devouring this palace's every door and window.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Some say this medieval church is where the poet Dante married his wife and also met the love of his life.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

An underground city of salt.

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

This deconsecrated church has seen many uses, from a tobacco storehouse to a cinema.

This sturdy, circular stronghold served as one of the forts that protected the Venetian Lagoon.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

Go inside to really appreciate this 500-year-old technological masterpiece.

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