In certain places in Japan, there are gigantic slabs of stone, erected centuries ago, that warn of environmental catastrophe.

“High dwellings are the peace and harmony of our descendants,” one reads. “Remember the calamity of the great tsunamis. Do not build any homes below this point.”

Some of the tsunami stones were placed there over 600 years ago, to warn anybody who came across them not to build homes beyond them. Others were placed more recently, like the one mentioned above that was put up in 1933. Built after several major tsunamis across the centuries, the tablets use several different methods of conveying their message. Some list death tolls, others simply tell all who see it to drop everything and get up high after an earthquake.

By design, they are supposed to endure through the centuries.

“The tsunami stones are warnings across generations, telling descendants to avoid the same suffering of their ancestors,” specialist in the history of natural disasters Itoko Kitahara told the New York Times in 2011.

The stones have often been adhered to, and have likely saved many lives from subsequent tsunamis. However, they highlight an interesting problem that we still haven’t come up with an ideal solution for: how do you convey danger to your descendants hundreds or even thousands of years in the future?

It’s not just a hypothetical problem, but something humanity has to address if we want to avoid needless deaths. Nuclear waste can last thousands of years, meaning any warnings we put up around waste storage sites will have to last long enough for our distant descendants to understand them. Simply placing it in a large structure isn’t enough, as the pyramids and every other large ancient structure that humanity has seen fit to rummage through over the years will attest. The message would need to survive across all cultural and language barriers that might arrive between now and when some future human stumbles across the nuclear waste in 7000 CE.

One idea, explored by Sandia National Laboratories in a 1993 report, is to make the landscape look as menacing as possible, in the apparent hope that humans thousands of years from now still have the NOPE reaction. The report proposed several designs, including a landscape of foreboding rubble made to look like the place had been purposely destroyed, and spikes jutting out of the floor at haphazard angles. One, known as the black hole, aimed to make people uncomfortable in several ways.

“A masonry slab, either of black Basalt rock, or black-dyed concrete, is an image of an enormous black hole; an immense nothing; a void; land removed from use with nothing left behind; a useless place,” the report reads. “It both looks uninhabitable and unfarmable, and it is, for it is exceedingly hot part of the year. Its blackness absorbs the desert’s high sun-heat load and radiates it back. It is a massive effort to make a place that is fearful, ugly, and uncomfortable.”

Making the place foreboding was only part of the plan. Messages would also be left at the site, with the hope that the terrifying architecture would reinforce that the message was a warning to stay away:

“This place is a message… and part of a system of messages… pay attention to it!

Sending this message was important to us. We considered ourselves to be a powerful culture.

This place is not a place of honor… no highly esteemed deed is commemorated here… nothing valued is here. 

What is here was dangerous and repulsive to us. This message is a warning about danger.

The danger is in a particular location… it increases towards a center… the center of danger is here… of a particular size and shape, and below us.

The danger is still present, in your time, as it was in ours. The danger is to the body, and it can kill.

The form of the danger is an emanation of energy. The danger is unleashed only if you substantially disturb this place physically.

This place is best shunned and left uninhabited.”

The report suggests that the language should be updated as often as needed, to give future generations the best chance of being able to decipher its contents.

This is far from the wackiest idea for how to deal with the problem.

In the early 1980s, the Human Interference Task Force attempted to come up with solutions, ready for a nuclear waste storage facility that was proposed to be built near Las Vegas. In true Vegas style, they came up with some strange and highly impractical ideas.

Of these, the Atomic Priesthood is clearly one of the coolest. Proposed by linguist Thomas Sebeok, the idea was that an “atomic priesthood” would be appointed by a council, who would then replace themselves as they grow old and retire and/or die. The priesthood – actually comprised of experts rather than the religious folk – would be responsible for passing on knowledge down the generations, partly through “artificially created and nurtured ritual-and-legend, which would be a ‘false trail’ for the uninitiated, who would be steered away from the hazardous site for reasons other than the scientific knowl[e]dge.” This would be used to ward off people visiting the sites, without giving away what they contain, should any nefarious actors come across it.

They would create an annual ritual, and the legend of what lies in these locations would be repeated, warding people off. In the meantime, as a backup, they would update any messages at the burial site every three generations or so, to ensure that it could be understood.

A more simplified version of this from Vilmos Voigt (sadly lacking priests) proposed that translations of signs near the site be updated every now and then.

Perhaps the strangest of solutions (and that’s saying something, given that a previous paragraph involved atomic priests) was proposed by author Françoise Bastide and semiotician Paolo Fabbri. They believed that the most sensible course of action was to breed “radiation cats“, that would change color when they came near radioactive material.

That was the easy bit. Like with the priesthood, the plan would be to install cultural legends and myths around cats that change color

AEON VIDEOS l The Ray Cat Solution from Benjamin on Vimeo.

The myths and fairy tales (why not) would then be passed on through poetry, paintings, and music. So hopefully when someone years from now came across a glowing cat, they would know to run like hell. Which, to be fair, you would probably do today as well.

Less bizarre ideas involved making sure that people could only access the sites using high-tech solutions, making it unlikely that people would stumble across it, figuring that anybody capable of getting in would have the equipment necessary to detect radiation as well. But it’s certainly less fun than stumbling across a field of spikes to an ominous message, only to be confronted by a glowing cat and a menacing-looking science priest.