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

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

A striking public sculpture representing the period of martial law in Communist Poland.

The silly symbol for an underground protest group is now scattered around the city.

Island wonderland for communist autocrats.

This nondescript building hides an entrance to an underground nuclear tunnel system.

Have a seat with the father of modern computing at this Manchester monument.

Finland's oldest astronomical observatory once played a crucial role in seafaring and timekeeping.

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

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Once a meeting point for great thinkers, and the midpoint of the country.

Climb to the top of its spiral spire for spectacular views of Copenhagen.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

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

This unique architectural wonder is home to luxury apartments.

This huge industrial sculpture looks like a UFO and a factory had a baby.

This giant urban staircase was built to keep the city's brave fighting men from getting waylaid in the red light district.

A sublime medieval path adorns the marble floor of one of the most beautiful Gothic cathedrals in France.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

The final resting place of the great navigator, or maybe his brother.

The world's largest wooden structure.

An awe-inspiring mosque in Morocco with one of the tallest minarets in the world.

While most shipwrecks are submerged, this ship in Cyprus ran ashore.