This Italian foot path winds through the mountains via 52 individual tunnels.

One of the most well-preserved castles in Italy also contains a rare medieval example of a port fortification.

This decaying complex from the early 1900s was once the site of massive iron and fluorite mines.

A formerly opulent Italian village is now a crumbling ghost town that no one really knows what to do with.

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

This 1st-century CE Roman bath sits under a carpark.

This half-finished "city of toys" was almost Italy's own Las Vegas.

The abandoned "Ghost Mansion" was left to decay in the mountains of Northern Italy.

The largest underground lake in Europe.

A fairytale island floats in the middle of Italy's little-known Lake Orta.

In the 9th-century this small spring-fed well became the location of daily mealtime miracles for one Saxon monk.

Under a church hides a forgotten 13th-century ossuary containing the remains of around 2,500 people.

Set amid the remains of a secret WWII airfield, this barn was preserved as a memorial to Allied agents who parachuted into Europe.

Museum celebrating the history of computers, especially their role in codebreaking.

A reportedly haunted 14th century church is curiously facing the “wrong direction.”

This ancient Bedfordshire church was abandoned when the village's population slowly began migrating to new towns.

This suburban British town holds secrets that would have made the druids proud.

A 19th century grave house with a unique message formed by the stone supports to the railing around the walls.

The first place where the scientific innovation known as radar was first demonstrated in Britain.

Hundreds of huge, centuries-old horseshoes adorn the walls of this nontraditional 12th-century castle.

The sanctuary seems to either float atop the water or sink into the dirt, depending on the water level.

England’s ancient oak tree has such an impressive girth, people have been hosting parties within the hollow trunk for centuries.

A humble homage to a gravedigger tucked within the dignified English cathedral.

A clumsy-looking flying locomotive rusts within sight of a busy rail station.