This 18th-century fort surrounded by a moat was used to store gun powder and ammunition, and now sits in the middle of a large part in Dublin.

This is the largest cemetery in Ireland and the first cemetery museum in the world.

The largest portal tomb in Europe has a capstone weighing around 150 tons.

This Bronze Age tomb is the centerpiece of a clearing within a beautiful Irish forest.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This former small-town cinema palace was built with the remains of a luxury liner.

Wonderfully preserved Victorian factory, complete with a preserved steam powered engine house.

Vast network of air raid tunnels beneath Lombardy's capital.

The longest and steepest staircase locks in the United Kingdom.

These caves are home to a small church and were used to age cheese.

The remnants of a classic 1970's British film.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

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

Much of what constituted mid-century Liverpool now litters a beach outside of town.

Human-made caves excavated to hide a secret society of wealthy pagans.

This magical museum celebrates the life and work of a seminal children's book writer (and occasional spy).

This antique prison is a tourist attraction with a sordid past.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

This incredible collection of vintage pinball machines can be played at 25 cents a pop.

Stepping away from the glitz of mobsters and casinos to learn about the other history of Vegas.

This century-old cinema is complete with musical interludes and boasts a rare projection system.

This centuries-old hotel hides a network of secret cellars and passages once used by smugglers.

This landmark of the Chicago silent film industry may not be in the picture business anymore but it still stands proudly.

Everyone remembers Laurie Strode from Halloween, but this is the house where most of the blood was shed.