A wunderkammer of gold and silver reliquaries and ancient saintly bones.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

Gargoyle head that brings good luck.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

The world's oldest grape-producing vine has survived four centuries of turmoil and even has its own anthem.

A whimsical bridge adorned with decorative dragons.

A Hungarian optometrist's charming collection of Asian art and curiosities.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

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

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

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

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

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.

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

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

The unusual sculptures are believed to be powerful political symbols.

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

A misnamed well, with a deep dark past.

Religious perseverance and cultural coexistence manifest in an architectural gem that multiple wars couldn't topple.

A Red Cross memorial museum at the site of the Niš concentration camp that operated for four eventful years during World War II.

A pair of connected skyscrapers form this symbolic gateway.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.