The social hall of this former factory is a Communist-era time capsule.

A Soviet-style monument, built after transferring the remains of heroes from their graves.

A crumbling monument to a now locally-extinct sport in Bulgaria's oldest ski resort.

An abandoned sanatorium building from the early 20th century sits in the forest of the Rila mountains.

At almost 900 feet long, this is Bulgaria's longest suspension bridge and the only way to reach the small village of Lisitsite.

The Bulgarian royal family exclusively used this ornate, now-abandoned train station.

Massive, unfinished broadcasting station stands as a monument to the fall of communism.

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

Sofia's legislative center is continuously reinventing itself.

These cascading falls resonate throughout the Bulgarian forest.

Crossing a suspension bridge above a forest is the only way to reach this 12th-century monastery.

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

A mysterious tunnel hidden in the shadows of a colorful, historic sanctuary.

An unfinished complex built for children from around the world sits abandoned on the Black Sea coastline.

A vast Communist-era exhibition space in the Bulgarian capital.

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

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

These natural cliffs look like they are a part of an old castle complex.

Ruins of an early Roman Christian church dating back to the 4th to 5th centuries.

Not far from a popular beach, an unfinished, abandoned mansion for Bulgaria's last communist dictator.

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

A striking symbol of the Bulgarian capital.

The second-largest Jewish temple in Bulgaria was deserted after World War II, seized by the communist government and then abandoned again.

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