Longest fortress system anywhere in Europe.

The world's largest historic armory was established by independent citizens to defend themselves from the wars of larger forces.

Double spiral staircases are not unheard of, but they are very rare.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

This 15th-century church houses priceless works of art from a range of Croatian artists.

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

Gargoyle head that brings good luck.

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

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

Just a few miles from Novalja, a strange geological oddity has left scientists baffled.

This beautiful Croatian fortress is haunted by legends of forbidden love.

Now harmless, this looming post struck fear into the heart of medieval troublemakers.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.

This modernist cinema has survived war and reconstruction to become a symbol of Lebanon’s revolutionary spirit.

This Ukraine alleyway has become its own little island of forgotten things.

This unique Lady Liberty is one of the only examples of the figure sitting down.

World's largest crossword puzzle spans the side of a towerblock, its clues scattered throughout the city.

A futuristic, brutalist masterpiece that is also strangely prison-like.

Seventy-five miles of limestone caves host more than a million bottles of wine beneath a sleepy Moldovan town.

A massive collection of petroglyphs dating back some 40,000 years.

A unique museum dedicated to culture and artistry of carpet weaving.