The 700-year-old fortress was the site of Count Orlok's castle in "Nosferatu."

A monument to the bloody fight against fascism in Slovakia during World War II.

An unusual cave filled with rare alien-looking aragonite formations.

A beautiful display of nearly 50 bells crafted with a unique design and distinct sound.

One of Hungary's most influential places of learning is also home to one of the world's most beautiful libraries.

These 13th century documents come housed in 18th century shelves organized by a 19th century historian.

This region of Slovakia boasts some of the most plentiful opal mines in the world.

One of the few cold geysers in Europe, its eruptions are powered by carbon dioxide.

An extraordinary museum devoted to the pop art legend created by Slovak artists.

An open-air museum of 18th-century homes and churches transported from various villages in Southern Poland.

The hollow trunk of this 650-year-old tree was used as a hideout by two Jewish brothers during World War II.

A monument to Poland's famous alleged UFO abduction case.

A somber memorial honors the hundreds of thousands of lives lost at this labor and extermination camp.

Old cabin-like homes in a rural community untouched by time are known for their vibrant and colorful window shutters.

This wooden mosque is one of the few remnants of medieval Poland's Muslim Tatar community in this deeply Catholic country.

A marker honors the brief peace found by a tormented artist in the fictional land of Kcymaerxthaere.

An engineering marvel at the time of its construction, this cross-border waterway sought to connect the Black Sea to the Baltic.

Open-air museum with a large collection of Soviet-era statues.

The pyramid and dome deep inside the Dzūkija forest are believed to channel divine energy.

A tiny traditional village keeps an ancient method of beekeeping alive.

Folky pharmaceuticals abound in this medicinal reliquary.

Ever-growing collection of devils in art.

This magnificent Art Deco church is a reflection of Lithuania’s turbulent history.

Museum deep in the catacombs of St. Michael the Archangel Church is explored by touch, sound, and smell.