Excavations at the Denisova Cave in Siberia have uncovered almost 80,000 stone artefacts that extinct humans left over a 150,000-year period. Collectively, they seem to show how technology developed by Denisovans evolved through the Stone Age, culminating with the production of spectacular bracelets, beads and tiaras about 50,000 years ago.

Denisova Cave lies in a river valley within the Altai Mountains, a few hundred kilometres from the Russian border with Kazakhstan, Mongolia and China. Ancient human remains in the cave …