This colorful artistic feature atop a Danish art gallery allows visitors to stroll through a rainbow.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

360° views of the city plus five floors of optical illusions and hands-on science.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

This 16th-century house tells the city's history through old artifacts and quirky tales.

The sign marks one of the endpoints to mainland Britain's longest overland travel route.

One of Europe's oldest libraries.

Just like in Hollywood, Madrid has also a forgotten walk of fame.

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

An encyclopedic collection of mammal penises.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

Eighty million natural history specimens call this gargantuan museum home.

One part local history, 99 parts gruesome haunted house.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.

Banksy's image of a naked man dangling from the window of a sex health clinic.

This enormous secondhand bookstore inside a Victorian train station sparked the "Keep Calm and Carry On" craze.

This giant wooden treehouse within a sprawling garden has its own eatery.

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

The sign at the garden gate reads: “These Plants Can Kill.”

The fantastic charm of England's oldest botanical garden has made it a place of writerly inspiration for centuries.

Ancient Egyptian wigs, South American feather headdresses, a bounty of anthropological artifacts in Oxford.