For over 30 years the walls of this Harlem schoolyard have been a gallery of street art by "Kings and better."

A collection of comics, graphic novels, animation and caricatures devoted to exploring this often overlooked art form.

A church of bones, decorated with 40,000 human skeletons.

This store decorated with Japanese and underground pop culture items has been the centre of Barcelona alternative fashion scenes for more than a decade.

This semi-secret storybook hedge maze is also the oldest garden in the city.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

This house's itty bitty size means no humans allowed.

A mysterious, abandoned building rotting on the Brooklyn waterfront.

An 1883 schoolhouse now home to collective of artists.

A former connection to City Island, it has been abandoned since the 1930s.

The greatest real estate coup of all time.

This historic building housed the surviving crew members of the Titanic, who were left destitute after the wreck.

Feral cats keeping the rodent population at bay all across Greenpoint waterfront.

This iconic tattoo shop has its own onsite museum with artifacts from the early history of modern body art.

A Japanese concept restaurant that feels like a party thrown by the monsters in your closet.

This faux-seedy Japanese arcade is made up to look like a maze of alleys straight out of a cyberpunk dystopia.

From Coke II to Google Glass, this exhibit features some of the most spectacular commercial flops.

An enormous playhouse designed to look like 21 stacked Lego bricks, with another 25 million colorful Legos inside.

This Danish art forest places loud works of contemporary art among the pensive silence of nature.

A crumbling hospital from the 1850s on Roosevelt Island.

A DIY art gallery/music venue/lecture hall dedicated to video game culture.

A floating cat sanctuary on an Amsterdam canal.

On Japan's Tashirojima Island, cats are king.

Terrifying derelict military hospital once housed a recuperating Hitler.