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

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

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

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

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

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

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.

Mysterious standing stone formations looks like a petrified forest.

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

"Unity, Creativity, Beauty."

Outstanding, eerie frescoes and decorations fill this 19th-century monastery.

UNESCO-protected ancient burial ground.

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

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

The site of many battles and tragedies, including the 40 maidens who leapt into the sea.

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

A flamboyant five-story building in Bulgaria resembles a crawling snail.

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

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

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

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

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

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