An otherworldly, fossil-rich cobble beach holds Viking graves, cairns, and other remains.

Iron Age grave stones and Viking burials, a short drive from Gothenburg.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

An intricately carved Viking church overlooks a glistening fjord.

Mounds, rune stones, and a 1,000-year-old church, left behind by Denmark's first two kings.

Countless grotesque faces stare out from this eerie Prague art wall.

An existential riddle in the world's largest ancient castle.

The first museum in the world devoted to sexual gadgetry.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

At one of Berlin’s oldest churches, visitors can place mosaic tiles to help restore a medieval mural.

A rare example of a German cemetery with traditional grave markers dating back several generations.

This curious sculpture represents the perseverance needed to take to the skies.

The ruins of an abandoned crematorium haunt an eerie deserted German cemetery.

A collection of artworks exclusively created by the mentally ill that was almost burned by Nazi culture police.

The oldest Jewish cemetery in Europe survived Hitler's Germany.

Striking occult iconography on a medieval German church.

This ancient ruined monastery has been destroyed by fire so many times that it seems like God hates it.

Among the ostentatious rococo ornamentation of this church, an image of death cuts the life-thread.

An intricate and amazing house built by architect Karl Junker.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

The attic of a four-century-old canal house hides a clandestine church.

This historic Amsterdam bar used to accept sailor's monkeys as payment.