Seventy-three thousand years ago, an early human in what is now South Africa picked up a piece of ocher and used it to scratch a hashtag-like mark onto a piece of stone.

Now, that stone has been discovered by an international team of archaeologists who are calling it the earliest known drawing in history.

According to their report, published today in the journal Nature, the stone predates the previous earliest known cave art—found in Indonesia and Spain—by 30,000 years. That would significantly push back the emergence of “behaviorally modern” activities among ancient Homo sapiens.