The legendary cliffside castle of three-time Voivode of Wallachia, Vlad the Impaler.

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

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

On the outskirts of the small village, an abandoned grassy field glitters thanks to the white stones of an ancient structure.

These cascading falls resonate throughout the Bulgarian forest.

Underneath this Byzantinian church lies a necropolis filled with ancient tombs and the ruins of previous churches.

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

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

The Grand Mall in Varna hosts one of the biggest collections of Soviet-era paraphernalia in Bulgaria.

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

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

A controversial art piece that harkens back to local folklore.

A curious memento mori hangs in the magnificent Cathedral of Segovia.

This small Spanish village still pays homage to the Spaghetti Western films that were shot there in the 1960s.

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

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

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

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

Rock carving created 1,300 years ago 75 feet off the ground.

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

Eastern Bloc nostalgia, anybody?

"Unity, Creativity, Beauty."

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

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