Outside a Viking museum sits a modern-day runestone made by a Swedish runemaster using traditional methods.

This giant subway sculpture celebrates the fruit that inspired the theory of gravity.

A plaque marks the house in Stockholm where the French philosopher René Descartes lived up until his death.

This grisly exhibit houses skeletons and weapons from a devastating 14th-century clash.

A man has revenged his true love's betrayal through tears and stone genitalia.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

At the foot of an active volcano sits a church miraculously spared by its lava.

Réunion Island's highest point is a 2 million-year-old volcano and a paraglider's paradise.

At the center of an island in the middle of the Indian Ocean is a deep chasm ringed by tall waterfalls.

Hiding the longest subterranean river known in the world.

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

The haunting concrete remains of a Nazi pebble crusher can still be found in this small French commune.

One of the great treasures of Neolithic art lies within this carefully constructed pile of rocks.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

An icy lake tucked among jaw-dropping alpine panoramas.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

A quaint medieval millhouse hovers surprisingly above the waters of the Seine.

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

His "Lionheart" is entombed separately from the rest of his body.

Guests can stay at a hotel in the former French abbey where lie the tombs of King Henry II and King Richard the Lionheart.

This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.

This professional clown's home is an outsider art wonderland.