The partially submerged ruins of a white marble quarry used in ancient Greece for over 1,200 years.

Rebuilt several decades ago, its striking murals prevent it from being reconsecrated as a church.

An homage to the medieval rulers of Bulgaria.

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

An ancient Thracian city where fire rituals were practiced on the largest cult altar in Southeast Europe.

In a long-dry lake bed, these groups of massive stone pillars bear a striking resemblance to clumps of everyone's favorite fungi.

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

An abandoned saucer-shaped monument in the Bulgarian mountains.

UNESCO-protected ancient burial ground.

The remarkably well-preserved final resting place of a powerful ancient Thracian king.

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

A Red Cross memorial museum at the site of the Niš concentration camp that operated for four eventful years during World War II.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

At this 16th-century monastery in rural Bulgaria, visitors can also spend the night.

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

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

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

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

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

One of the largest mines in Bulgaria is now home to a vast museum more than 100 feet underground.

Founded in the 4th-century, the town of Pernik plays host to the Surva Carnival⁠—a magnificent display of masked Kukeri dancers.

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

Sofia's legislative center is continuously reinventing itself.