A perfectly circular stronghold constructed in the 10th century is now a nucleus of Viking culture housing a museum, village, and reenactment of an epic Viking battle.

Preserved "bog person" that is over 2,000 years old.

The northernmost point in Denmark is a turbulent sandbar created by two clashing seas.

This Danish rock field is actually a sprawling ancient cemetery holding the bodies of 700 Vikings.

The world's largest maze is a nature park with nearly 200 decision points.

Iron Age "bog person" preserved for over 2,300 years.

This secret collection of the strange and occult was rediscovered in a forgotten room of an old house.

An enormous playhouse designed to look like 21 stacked Lego bricks, with another 25 million colorful Legos inside.

A natural wonder in south Denmark.

Old Danish castle immortalized in Shakespeare's Hamlet.

This colorful artistic feature atop a Danish art gallery allows visitors to stroll through a rainbow.

Six beautiful wooden giants are hidden around Copenhagen.

Vortex-shaped aquarium hosts Europe's largest school of piranhas and other ocean creatures.

A walkable map of the world, made from soil and stone by one man.

Museum celebrating the ocean, with the largest wunderkammer dedicated to sea exploration.

Breathtaking and huge 430 year old maps of Italy.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

A striking 12th-century-style castle built on the edge of a cliff.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Some of the smallest works of art in existence.

An abandoned 19th-century iron factory perched along the outskirts of an idyllic village.

Thousands of slain Soviet soldiers are buried within the shadow of this enormous obelisk.