Buried five stories underground, this Soviet bunker is packed with gas masks and Cold War paraphernalia.

The first museum in the world devoted to sexual gadgetry.

The last municipal pneumatic post system in the world was in operation for over 100 years, and may run again.

This artificial cave looks like something out of a fairytale.

The hidden lair of an alchemist rediscovered in a 2002 flood.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

This quiet, unassuming spot in Budapest was the birthplace of the bloody 1956 Hungarian Revolution.

Museum dedicated to the terror regimes of Hungary.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

Some of the greatest minds in the history of Hungarian art and science converged in this café.

A marvel of technology a century ago, this disused power station now offers a lovely glimpse into the industrial design of the past.

A Hungarian pharmacy museum with a box full of mummy powder.

The largest statue of this convex, homogeneous object with just one stable and one unstable equilibrium point.

Central Europe's largest collection of mini-bottles is on display at this museum devoted to a bitter Hungarian liquor.

A relic of World War I that now exist as a piece of public art.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

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

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

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

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

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

Known as the Hintz House, this medieval pharmacy has been an apothecary's haven for nearly 450 years.

After sitting unused for decades, this abandoned communist infrastructure became a wildlife utopia.