What will the inhabitants of Earth be like over the next 100,000 years? Will they even be human, or some other civilization of animal or alien being? These questions are at the heart of Into Eternity, a beautiful and extremely fascinating Danish documentary about ONKALO, the ambitious nuclear waste repository near Olkiluoto, Finland, which will bury thousands of tons of spent uranium from a local power plant in an extensive underground tunnel system.

Directed by conceptual artist/filmmaker Michael Madsen (no, not the "Mr. Blonde" one) and co-written by Jesper Bergman, the film plays like science fiction, but it's alarmingly contemporary. For us, anyways, but Into Eternity is structured as if it's not intended for a modern audience. It's a relic-to-be. In an eerie narration, Madsen addresses future viewers, whether or not they will understand his English-spoken warnings and questions, urging them not to curiously venture into the tunnels as if it were an archaeological find, like the Egyptian pyramids.

Yet in asking the hypothetical later audience about what has happened to the human race and the Earth itself, wondering if another ice age has come, if the world is less populated, etc., the film really directs such contemplation at the present -- both at those of us in the audience and the scientists and planners interviewed onscreen. Among the many issues of safety, the most interesting regards the communication of ONKALO's existence to later generations and societies. Will markers with modern words or currently understood symbols and imagery be useful to a people or creatures with unimaginably different or evolved language? Could an oral tradition of continually passed-on and presumably modified warnings be trusted?

Or should the repository be figuratively swept under the rug to avoid the dangers of human curiosity and greed (the copper canisters used to store the uranium will no doubt be coveted by future treasure hunters)? It's amazing how much is pondered and dauntingly projected about humanity in a short span of 75 minutes, in a film about a single nation's little-known plan for what's basically a $4.5 billion self-storage unit with a 100,000 year lease.

You'll be left to wonder about the answers to the film's questions long after it ends, because neither Madsen nor Into Eternity's featured experts offers any conclusive statements or concrete plans (for outside the tunnel, that is). One individual points out that since the project has about another century until completion, there's plenty of time for later discussion and debate about safety, markers and other matters that would seem to be more pressing.

That argument and attitude kinda seems too pass-the-buck given the project's otherwise exigent nature. Yet it contributes to the underlying despair that permeates the documentary and the very concept of ONKALO itself. Between Into Eternity and the global warming-themed North Pole travelogue Into the Cold, Tribeca seems really intent on bringing me into a gloomy mood as far as the hope for both humanity and the planet is concerned.

Unlike Into the Cold, though, Madsen's film has no political agenda. It is neither for nor against nuclear power, and it doesn't take any sides regarding the construction or later maintenance of the repository. And though it elicits whatever feelings you may have about energy sources, the environment and the fate of man and life on Earth in general, there is no direct warning or advocacy to people in the 21st century. It's simply an eerie look at a sort of time capsule, while also being a time capsule itself.

A man involved in the physical digging (they have a more preferred term for their explosive tunneling, but I unfortunately can't remember what it is) admits his job is sometimes like time travel, because he can go into the ground in the morning, when it's warm and sunny outside, and exit at night to find it has snowed all day, making it appear like much more time has passed. Into Eternity gave me an almost relative sense of temporal confusion:

I started out in some ignorant past, for which this was science fiction; then I was shot into the future, or a number of potential conceivable futures, where I could have the right perspective of viewing the film as a historical artifact; and then I was ultimately returned to the present with a feeling of general insignificance -- but not necessarily in a useless or otherwise depressing way, though I'm sure others will come out feeling more forlorn.

An audience member at the Tribeca screening I attended brought up H.G. Wells. And watching Into Eternity is indeed very much akin to reading The Time Machine. Only it's far more real and far more scary, as the underground threat here is invisible and has a longer lifespan than the Morlocks of Wells' story. But in the end, like Wells' traveler, our new found knowledge and perspective has little affect on our day to day life, at least outside our minds.