The Polish capital has had a deep connection to its guardian mermaid for almost a millennium now.

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.

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.

A statue honors the children who fought Nazis in Poland.

A collection of old neon signs from all over Poland line a secluded courtyard.

A menacing statue of this mythical creature can be seen at the legendary site of the monster's lair.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

A huge wooden clock that is so beautiful its creator was forcibly blinded.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

This man-made mound monument was built out of soil from all across the Polish empire.

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

The site of the first battle of World War II.

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

An underground city of salt.

An homage to the medieval rulers of Bulgaria.

Sofia's legislative center is continuously reinventing itself.

This massive stone and steel monument remembers a century-old battle that cost thousands of lives and nearly destroyed the city.

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

"Holy Wisdom" overlooks the city that became its namesake.

"Unity, Creativity, Beauty."

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

This once-grandiose behemoth of a monument from the socialist era now sits quiet and closed up.

UNESCO-protected ancient burial ground.