But these efforts are still digital. Even if societies manage to keep adequate records, Kunze contends, we’re bound to hit a wall: Either storage space will run out or the environmental costs of maintaining it will grow too large. In the latter scenario, our data would have to be ruthlessly removed to reduce energy use from digital storage, he says. “This will be executed by algorithms, and therefore the pictures our grandchildren will have of our time will be dictated by machines.”

Kunze believes an inevitable path toward environmentally friendly architecture will lead to a decline in our physical presence, too. Design movements such as “cradle-to-cradle , ” in which construction materials are clean, renewable, and completely recyclable, will mean that buildings no longer remain as relics. “We have to become a green society, otherwise we will not survive on this planet,” Kunze says. “But future archaeologists will only find traces until the 21st century. After, there will be just pure earth.”

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Kunze’s quest began more than decade ago, when he was studying art and art history at the University of Arts and Industrial Design in Austria. He realized the storage potential of clay, and as his concerns grew in the years following, he came to the conclusion that humanity needed a ceramic time capsule. In 2012, he says, he contacted the company that extracts salt from Hallstatt’s mine, and they agreed to provide space for him to house his vault inside.

So far, Kunze has created all the large tablets himself in his studio, and a few private companies are helping with the production of the microfilms. Some prototype samples of these have been produced, now he just needs content to fill more. As word about the project has spread, a handful of researchers from universities in countries as far afield as Australia have reached out to Kunze to learn more about it. One professor at the University of Vienna is looking into how music and sound might be stored on ceramic, too.

As the project slowly starts to take shape, some are worried that its own place in collective memory may ebb over time. “The thing I don’t like about the time capsule is the sense that it’s frozen,” says Richard Ovenden, the director of the Bodleian Libraries at the University of Oxford. “Information is much more likely to be kept if it’s used. The danger is that [Kunze’s project] will end up being forgotten.”

To avoid this, Kunze plans to distribute ceramic tokens around the world to everyone who either funds, contributes to, or advises on the project. Every 50 years, starting in 2070, he says, holders will meet to keep the memory of the capsule alive and to discuss if it needs to be reopened. The location of the mine will be carved onto each token, and it will require geological knowledge similar to our own to find it, especially as land shifts with time. This would be a safeguard against unwanted discoveries if for some unpredicted reason—nuclear war, say—human civilization disappears or regresses to the Stone Age.