This legendary city has been a tourist attraction for centuries.

Northern Ireland's Brobdingnagian stepping stones.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

This Parisian café sticks almost exclusively to an ethos of reuse.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

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

Macabre astrological automaton clock dating to the late 1400s.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

The oldest stone house in Paris was built by its most famous alchemist.

Hot springs monkey spa in the middle of Hell's Valley.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

A lake formed in the basin of a massive impact crater takes the shape of an unbroken ring when viewed from above.

A lake in the middle of the tundra of Quebec is said to be the purest freshwater lake on Earth.

What better way to honor a pioneering anatomist than by preserving his severed head like a specimen?

One of the highest emergency huts in the world has been waiting almost a century to give imperiled climbers a place to lie down.

A tree that defies gravity grows in an ancient ruin.

A secret hatch containing two parchments was discovered in this statue over 40 years after its installation.

The forbidden island of the Tuscan Archipelago may still contain buried treasure.

A modern sliver of architecture in Roma.