The final home of the legendary Danish sailor said to have lived to be 146 years old.

A beautiful photography exhibition space housed in a former church.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

At this archaeological site, visitors can explore the ruins of the capital of the former Roman province of Moesia.

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

Ruins of an old water tower that look like a horror-film castle.

Serbia's master of striking memorials erected a forgotten, hidden gem in the hills outside a tiny village.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

A bridge destroyed three times: once as a ruse, then in an actual attack, and finally for the movies.

This Croatian computer club features such gaming relics as the infamous Virtual Boy and an 8-bit Pacman machine.

A musical instrument played by the sea.

An ethereal glowing blue ocean cave in Croatia.

Once the legendary capital of the Dacian Kingdom, this city has been reduced to mere ruins.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

This once-derelict building is now one of the most beautiful bookstores in the world.

A micro-communist utopia in Spain with no police, no mortgages and full employment.

Blue-green pools and smooth stones comprise one of Spain’s most idyllic hidden wonders.

The morbid items in this small and hidden museum are not for the weak stomached.

Bacteria and algae give the salty water its bubblegum hue.

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

This 11th-century structure is one of the oldest churches in Romania.

A spooky spot along the road where things mysteriously seem to move uphill by themselves.

Romania's triumphal arch looks out over Bucharest.

This enormous abandoned prison was once dubbed the "Bastille of Romania."