A World War II evacuation tunnel turned into a history display of Croatian state and people.

An idyllic traditional timber village on a picturesque hill was built for a film.

Backwards hour and minute hands and a timing mechanism that fluctuates with the temperature led to this clock tower's local nickname.

For over 40 years, this quaint little house has teetered on a rock in the middle of a river.

A Serbian church lit by chandeliers made of weapons.

The unusual sculptures are believed to be powerful political symbols.

This small bronze pyramid marks the center of Belgrade, but some say it is a Masonic symbol.

Structure built from the skulls of vanquished foes.

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

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

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

A supersonic jet stands on a pedestal in this rural village as a monument to military aviation.

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

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

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

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.

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

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

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

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.

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.