An ornate private entrance to the Vienna subway built specifically for the emperor.

This museum is dedicated to the little known ancient Roman history of Vienna.

A magnificent collection of imperial armor and weaponry.

The Habsburgs' royal collections of art and wonders.

This easily overlooked memorial immortalizes the scars from the 1956 Hungarian Revolution.

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

A glimpse into the festive and private lives of medieval Europe.

Museum devoted to the artificial language of Esperanto.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Handsomely crafted representations of our round planet.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

The big toe of this towering monument to a Croatian national hero is worn from years of superstitious rubbing.

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

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

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

Longest fortress system anywhere in Europe.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

This picturesque monastery at the base of a cliff is a peaceful oasis open to all visitors.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

Bridge that died in war and was resurected.

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

An abandoned cable car station located on the Danube stands like a haunted house above the river.

Time stands still at this serene burial ground in the center of Budapest.