Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

Something's watching you.

No one knows who built this strange cave of worship or exactly why.

A memorial museum to the political prisoners who were held at Sighet Prison, once one of the most feared places in Romania.

This enormous abandoned prison was once dubbed the "Bastille of Romania."

Once the legendary capital of the Dacian Kingdom, this city has been reduced to mere ruins.

The ancient Greek Titan guards this massive dam holding a lightning bolt to symbolize electricity.

Romania's triumphal arch looks out over Bucharest.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

The romantic botanic tunnel feels like a well-kept secret.

This snug medieval lane is one of the narrowest streets in the world.

One of the oldest churches in Romania is believed to have been built on the site of a pagan temple.

This once-derelict building is now one of the most beautiful bookstores in the world.

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

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

Some call this eerie forest of crooked trees the "Bermuda Triangle of Romania."

This massive underground salt mine now holds a sci-fi theme park in its depths.

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

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

A small memorial to a deadly night in Serbia that shook the world before it was swept under the rug.

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

This former monastery is still a revered religious site.

Once a bridge over the River Begej, now high and dry.