Yugoslavia's biggest underground airport lies in ruins.

A forgotten and crumbling Yugoslav monument to the victims of fascism.

Oriental bazaar in the heart of Sarajevo.

A small museum built by a family that survived the Siege of Sarajevo.

Believed to be the country's tallest waterfall, the Njupeskär is actually much smaller.

Gravity seems to fail at this intriguing Swedish attraction.

Despite the groans of archaeologists, this astounding groups of Bronze Age petroglyphs have been painted red for tourists.

The rock carving that became an internet meme.

Sweden's southernmost prehistoric rock art is hidden just outside Gothenburg.

From Coke II to Google Glass, this exhibit features some of the most spectacular commercial flops.

Iron Age grave stones and Viking burials, a short drive from Gothenburg.

Walking through this narrow gorge will make you feel like you've fallen into a fairytale landscape.

During World War II, a number of important sculptures and paintings were moved to this castle for safekeeping.

Water and windows define this defensive Italian well.

This Roman underground canal was the longest tunnel ever built until the late 19th-century.

Unscathed for almost 2,000 years, the best preserved Roman triumphal arch is in a small southern Italian city.

The underground sanctuary of a mysterious ancient Roman religious cult contains an exquisite traditional fresco.

One of ancient Etruria's most spectacular archaeological sites with impressive necropolises and rugged landscape.

This picturesque Umbrian city has a subterranean side that has long remained hidden.