The largest underground church in Europe.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

This museum houses an imposing skeleton army comprised of creatures great and small.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

A haunting collection of the vanished and disappearing natural world.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The oldest (maybe) swimming pool in Iceland is a stunning oasis built into the side of a lush hill.

This rusting remnant of the local herring industry is being given a second life.

This black church sits alone among a field of lava rock.

A trio of hidden hot tubs takes advantage of Iceland's natural geothermal vents.

The largest whale museum in Europe allows visitors to walk among life-size giants.

This wrecked airplane has been sitting on a black sand beach since the 1970s.

A winding, blood-red tunnel of hardened lava navigable by foot.

An encyclopedic collection of mammal penises.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.

This modern monument to pagan belief looks like it was transported straight from ancient times.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

Rising from the sea like a stone monster.

Staves, storm-calling, and of course, necropants.

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