An ethereal glowing blue ocean cave in Croatia.

This memorial to local World War II heroes is slowly being reclaimed by nature.

The only known mosaic depicting the Greek god of sleep, Hypnos.

This World War I fortress is the perfect place to catch a Montenegrin sunset.

Its frescoes depict the likeness of Marshal Tito, Karl Marx, and Friedrich Engels burning in hell.

Inside this small chapel tucked away in the forest is one of the most well-preserved Danse Macabre frescos.

A forgotten monument to Yugoslavian freedom.

Humble beginnings for one of the world's most famous scientists.

Dive for drinks at Croatia's first and only underwater winery.

Longest fortress system anywhere in Europe.

The oldest arboretum on the Dalmatian coast doubles as the gardens of Kings Landing in "Game of Thrones."

This unique structure allowed boats to bypass underwater mine barriers in the channel to enter the harbor.

A unique two-level bridge designed to honor a king.

This military tunnel dates back to World War II and provides visitors with a little wartime adrenaline.

Now abandoned, the world's first torpedo factory is crumbling into the sea.

This narrow fjord-like bay is the largest ria in the Mediterranean Sea.

Maze-like streets filled with vibrant murals draw visitors to this Istrian town.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

Inside this mansion turned museum, the works of prominent Croatian artists are on full display.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

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

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

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.'