A hidden art gallery in an abandoned Warsaw fort.

The final resting place of more than 200,000 people, this is one of the largest cemeteries in Europe.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

A forgotten graveyard lost in the tangles of an overgrown garden.

A museum in the childhood house of a medical pioneer.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

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

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

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

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

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

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

Once the home of a hermetic monk, this cave now houses a small church.