At the right time of day, sunlight floods through the roof of this cave and illuminates the small pavilion hidden within.

A limestone wonderland of water and subterranean secrets.

A white Buddhist temple with a golden restroom.

Long-secret natural history museum, featuring the skull of a "Terror Bird."

Beautiful antiques and obscure engineering artifacts trace the evolution of phones from rare luxuries to ubiquitous.

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

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

Electrical curiosity museum housed in an old transformer station.

A fake Transylvanian castle houses a cathedral of antlers.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

Sitting beneath an unremarkable residential building is a museum devoted to classic Pinball.

A museum in the childhood house of a medical pioneer.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

The abandoned "Red Star Train Graveyard" is the final rusting place for precious artifacts of train history.

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

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

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