A striking symbol of the Bulgarian capital.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

Bridge that died in war and was resurected.

This unique structure allowed boats to bypass underwater mine barriers in the channel to enter the harbor.

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

Longest fortress system anywhere in Europe.

Where the lovelorn find a home for their sentimental keepsakes.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

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.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

Op-art architecture designed for happiness.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

It houses the remains of a 17th-century version of the Titanic.

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

An exquisite monument dedicated to fallen Partisan soldiers and anti-fascist fighters of Yugoslavia through symbols of gears and flowers.

A beautiful mountaintop mausoleum devoted to a Montenegrin icon can't seem to make everyone happy.

On top of a resort town as old as the Bronze Age sits an incredible war memorial statue overlooking the beaches below.

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.

A tiny church on a man-made island in the Adriatic.

A curious cave church carved into the face of a cliff.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.