A 2,000-ton rock resting in a state of a delicate balance.

This 17th-century pub once had a hole in its wall so the neighboring blacksmith could easily access beer.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

The remains of the concrete ship can be seen during low tide.

The only substantial part of Nazi Germany's formidable defensive line through Northern Italy that survives today, largely intact.

This Gothic Revival castle used as a shooting location for "The Secret Garden" and other films.

This former military airfield's claim to fame came from a lucky accident during the Second World War.

This former Welsh metal factory is now a lovely abandoned relic but was once one of the industry's world leaders.

This lonely cast-iron structure is the only wave-washed lighthouse of its kind left in all of Britain.

The decaying ruins of Wales' first asylum for the mentally ill.

The oldest continual pilgrimage site in Britain was supposedly created by a gruesome beheading.

This abandoned asylum in Wales might look haunted, but it's still beautiful.

The sign at the garden gate reads: "These Plants Can Kill."

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

The largest manmade caves in Europe now function as a motorbike club's headquarters.

The deepest sinkhole in Central Europe comes with a grisly tale and an unusual nickname: “The Stepmother Abyss.”

This former quarry is now a picturesque gorge that hides a sunken lake.

Fall down the rabbit hole into a surreal journey of human consciousness "from ass to soul."

This TV tower once secretly housed a GDR intelligence team.

The site of good faith and good nature in the fictional world of Kcymaerxthaere.

The music is over at the Ballhaus Riviera Ballroom, but the ballroom remains in haunting disrepair.

This conical hill was built as a testing ground for an engineer known as the Glider King.

A century-old shot ball factory tower is open to the public once a year.

The ruined remains of the airport Claus von Stauffenberg departed in his failed attempt to kill Adolf Hitler.