Michael Madsen’s #documentary Into Eternity takes a look at the Onkalo long-term nuclear waste facility, located on the west coast of Finland. Onkalo—“hiding place”—is designed to last for at least 100,000 years; an ambitious proposition, considering that the oldest man-made structures on Earth are less than 10,000 old.

Ensuring structural integrity for tens of thousands of years—or, as one official points out, just the next hundred—is no small requirement, but the designers also have to consider one of the most challenging #design problems in the world: how to communicate with unknown civilizations with whom we may have very little in common. What if, thousands of years from now, someone stumbles on Onkalo and doesn’t realize the danger? Imagine a 19th-century archaeological expedition encountering nuclear waste buried by ancient Egyptians.

A bit on the artsy side, but still, a fascinating—and often beautiful—look at where some of the worst stuff on earth is kept away.