The gutted remains of this Estonian mansion are a monument to a tragic love.

This abandoned fighter jet launch center is now a haunting street racing course.

First point in the Struve Geodetic Arc, a 19th century undertaking to measure the Earth's size and shape.

The secret cells in the basement of the KGB's Estonian "Grey House" have been preserved as a grim Cold War museum.

A black cat protests the City Guild in Riga's Old Town.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

Once the home of a hermetic monk, this cave now houses a small church.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

Museum dedicated to the terror regimes of Hungary.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

A church of bones, decorated with 40,000 human skeletons.

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

This massive concrete sculpture is said to be the heaviest communist monument on Earth.

An homage to the medieval rulers of Bulgaria.

An abandoned saucer-shaped monument in the Bulgarian mountains.

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

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

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

This historic black and white monastery is one of Bulgaria's architectural jewels.

"Unity, Creativity, Beauty."