This piece of early engineering is rather unknown despite its location in the heart of Madrid.

The graffiti-covered remnants of a former triangulation station are balanced precariously on this California peak.

A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

More than 700 species live within this murky marvel of a swamp on California's coast.

It should come as no surprise that the world's largest artichoke lies in the town that calls itself the "Artichoke Center of the World."

Enormous crabs, bioluminescent jellies, and other amazing creatures from the ocean’s depths—some of which are in an aquarium for the first time ever.

A dozen cast iron leopards stand guard along the length of Aberdeen's Union Bridge.

This historic Victorian hotel has a scandalous history of affairs and murder.

This statue is the only female representation of Rome's "talking statues."

A huge enchanting public park just outside the ancient walls of Rome.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

The mysterious empty cupola behind the monumental arch points to an ancient prophecy of Delhi.

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

Tucked in the back of a flower shop, its collection details the fascinating history of the Netherlands's iconic symbol.

This towering church is home to a world-famous organ and a treasure trove of medieval art.

The remains of a grand castle that may have inspired Bram Stoker's Dracula.

This painting of a beloved dog will be on display at the Scottish National Gallery at long as the museum exists.

It's said this was once the home of King James V's pet lion.

These formal gardens were designed to be admired from the vantage point of the castle.

The location of a citizen uprising that led to a gruesome act of mob justice.

This charming old building's loose connection with the Scottish Reformer is what saved it from demolition after it split apart.

Now home to a drinking establishment, this building has a macabre history.

The largest collection of Indigenous Australian artifacts in the world, and the rare museum where wood-and-glass cabinets have trumped interactive exhibits.

A bronze statue of a low three-legged seat commemorates a piece of furniture that started a riot.