This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

This unassuming chapel in Portugal plays host to a ghoulish collection of bones.

Perhaps the most spectacular grotto along the Algarve coastline.

Cycle the solar system—from the sun to Pluto—right here on earth.

An incredibly well-preserved piece of ninth-century Viking poop.

Once the largest unsupported dome in the world, beating out the Pantheon and St Peters in Rome.

This beautiful "lagoon" is actually a toxic soup filled with cars, carcasses, and trash. When warnings couldn't stop people from going for a dip, the town dyed it black.

A labyrinthine underworld of tunnels and caverns hides beneath the city.

An engineering error ensured this cavernous 350-foot-long subterranean thoroughfare was never used as intended.

This 20-foot mountain is made up of some 15,000 mannequins—if you visit, you can even take a piece home with you.

The curious and tiny collection contains some very odd objects.

There's a strange stone hoodoo towering atop a wooded hillside and no one is quite sure how it got there.

The view from this giant Stone Age toad is unexpectedly beautiful.

This iconic Peak District ridge was once one of the busiest roads in medieval Britain.

This unique sculpture of a steelworker is hidden amid the trees of Sheffield.

Long-secret natural history museum, featuring the skull of a "Terror Bird."

Cemetery established by the Victorians as a solution to the overflowing graveyards.

One of the last remnants of the Bessemer process that revolutionized steel production during the industrial age.

The near loss of the stately fireplaces at this medieval castle spawned some of Britain's most crucial historic preservation laws.

A giant piece of cutlery designed to remind us about the origins of our food.

This gorgeous space is England's largest independent library outside of London.