Semi-precious Blue John stones have been mined in this cavern system for centuries.

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.

This landmark Victorian folly rewards visitors with spectacular views over the Peak District.

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

On a site with a long military history, a 1980s shelter.

A metal tree emits eerie, melodic notes on top of Lancashire's Crown Point.

A harrowing sculpture commemorates the four people shot down during the workers strike of 1842.

After mysteriously refusing to surrender at the end of World War II this sunken submarine was only salvaged in a search for Nazi gold.

The grand complex of buildings that comprise Liverpool's Exchange Flags includes a vast World War II bunker that has been frozen in time.

Pyramid shaped monument with a tall tale attached.

Created as a punny statement about genetic engineering this monstrous hybrid statue has become a beloved icon.

Charles Dickens described the concert room in this amazing Victorian hall as "the most perfect room in the world."

19th century tunnels burrowed under Liverpool.

The red letters in the literary pavement leading to the library form a mysterious code.

This aging storage facility is the world's largest brick warehouse.

This abandoned lock-up was saved because of its connection to a local football team.

The second-longest pier in the U.K. stretches a whole kilometer into the Irish Sea.

Hidden behind a wall, Spanish nuns distribute their signature sweets on a revolving tray.