Neanderthals seem to be the first humans to make synthetic materials

Birch bark was heated in underground chambers to create a tougher adhesive.

https://arstechnica.com/science/2023/06/neanderthals-seem-to-be-the-first-humans-to-make-synthetic-materials/?utm_brand=arstechnica&utm_social-type=owned&utm_source=mastodon&utm_medium=social