Legend says this sacred tree was a gift from goddess Athena.

This legendary city has been a tourist attraction for centuries.

The hallucinogenic center of the ancient world.

Monasteries on rock pillars, once accessible only by frayed ropes.

If you visit Santa's village, you can get your passport stamped to show you crossed into the Arctic Circle.

Roughly 17 million letters to Santa have found their way to this Arctic Circle post office.

A replica of the home of a famous fictional troll family.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

The Guardian of Tallinn.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Now harmless, this looming post struck fear into the heart of medieval troublemakers.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

A little sculpture with a large wardrobe.

Climb inside an iron crystal magnified 165 billion times its normal size.

The Habsburgs' royal collections of art and wonders.

The topiary maze at the Habsburg hunting lodge.

Stockholm's narrowest alley is barely over two feet wide.

The library's graceful rotunda is like a bibliophile's temple.

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

This unusual piece of Renaissance art depicting the bodily horror of crucifixion and skin disease may have been inspired by fungus-induced hallucinations.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

When the rain falls, this drain system turns into a musical instrument.

The "Prussian Versailles" that is as glorious today as when it was built.