A spectacular Petrine Baroque summer palace commissioned for Catherine I by Peter the Great.

The widest natural waterfall in Estonia is a sight to see in all seasons.

This stunning limestone waterfall is the highest in Estonia.

Relics from an era long gone, sit idle outside this Estonian museum.

A decommissioned submarine base makes a great space for graffiti art.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

A striking symbol of the Bulgarian capital.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

A collection of art from Bulgaria's time as a communist state.

"Unity, Creativity, Beauty."

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

The ceiling of Prohodna Cave in northern Bulgaria affords a peek at the sky via two deity-sized-eye-shaped holes.

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

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

A massive cave once a secret military base is now home to thousands of bats.

A decaying, yet still functioning, work of communist architecture.

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

An abandoned saucer-shaped monument in the Bulgarian mountains.

A single light illuminates one man's overshadowed contributions to street lamp history.

Home to the organ played at General MacArthur's funeral.

The final home of the most famous horse of the American Civil War.

This "castle" is actually a limestone and quartz formation hidden along a trail.

The hide of Stonewall Jackson's equine sidekick is on display not far from where the ashes of his bones are buried.

This war hero's old shop remembers the fine line between medicine and quackery during the Revolutionary War.