A morbid secret lies hidden within the beautiful walls of the Boston Athenaeum.

A beautiful Victorian-era cemetery, complete with a miniature village.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

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

Legions of Roman soldiers bathed in this ancient spa complex under a Budapest transit station.

300 years of pharmaceutical history on display.

The remains of an entire Roman city can be explored in this interactive museum.

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

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

Hungarian self-built castle.

This hidden art nouveau gem was designed by an architect in search of a national style.

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.

Hungarian mummies in beautiful painted coffins.

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

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.

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

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

Museum dedicated to the terror regimes of Hungary.

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

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

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