Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

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.

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

Nordic giants resurrected from the sea and restored to their former greatness.

The original home of the Lego has a huge amusement park dedicated to the iconic plastic toy.

Four alabaster giants contemplate the tides on the shore of Denmark.

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

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

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

An abandoned textile factory on the "island of crows" was home to Estonia's first workers' strike.

Legend says lovers who hold hands while venturing along this stone jetty and kiss at the end will remain together forever.

This dizzying tower was built to better broadcast the 1980 Moscow Olympics.

The Guardian of Tallinn.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

The ruins of an Estonian prison are drowning in the quarry lake where the convicts were once forced to work.

Mysterious craters may have been home to an ancient cult.

Sofia's legislative center is continuously reinventing itself.

An homage to the medieval rulers of Bulgaria.

A vast Communist-era exhibition space in the Bulgarian capital.

A gigantic statue of a Russian soldier watches over the ancient city of Plovdiv, a prominent reminder of the Soviet period in Bulgaria.

A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

A magnificent, glittering building tucked into a tiny Bulgarian mountain town.