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

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

A futuristic, brutalist masterpiece that is also strangely prison-like.

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

A sinuous path among steep cliffs creates a stunning sight in southwestern Serbia.

Beautifully carved tombstones fill this unmarked graveyard, uniquely situated near the village's famous stone wine cellars.

Moss and stone turn this waterfall into an otherworldly liquid veil.

A giant portrait of an ancient king looms over the river.

Stone age urban planning.

This military mausoleum captures the solemn grandeur that most memorials only aspire to.

These delicate sand pyramids look like naturally occurring gothic spires.

Site of the 1889 murder-suicide of crown prince Rudolf and his lover Mary Vetsera.

"Medieval" castle built in the mid-20th century by one family.

A self-proclaimed libertarian micro-state on a tiny bit of disputed territory between Serbia and Croatia.

Religious perseverance and cultural coexistence manifest in an architectural gem that multiple wars couldn't topple.

One of the largest barracks of the Austro-Hungarian monarchy's military is now an abandoned ruin.

Hungarian self-built castle.

The romantic garden was the epicenter of the Hungarian art scene in the 1880s.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Built to repay the sins of the father, this church is home to one of the most valuable works of Western art.

The world's oldest surviving anatomical theater, where "the dead are pleased to help the living."

A complex, nine-layer maze on the grounds of a Venetian doge's playground.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

The shell of a medieval fortress offers commanding views of the area it once protected.