In the 1600s, Europe's most educated minds looked at a swarm of flies and declared them beasts born from rotting mud. Spontaneous generation wasn't fringe thinking; it was scientific consensus stretching back to Aristotle. Then a German girl who started collecting caterpillars at 13, legally barred from oil painting by the guilds, dismantled the whole myth with a paintbrush, a magnifying glass, and decades of patient observation.

This episode follows Maria Sibylla Merian from the bedroom entomology lab of her childhood, through the embroidery lessons that doubled as a Trojan horse into Nuremberg's walled gardens, to the self-funded scientific expedition she launched to the jungles of Suriname at age 52. It also covers the posthumous vandalism, publishers inserting invented bugs into her books, that let 19th-century critics dismiss her, and the modern rediscovery that restored her place as a founder of ecology.

• Why spontaneous generation made twisted sense before microscopes, and what it took to disprove it
• Gouache on vellum: how an unforgiving medium became a precision scientific instrument
• The Jungfern Company: teaching rich men's daughters as VIP access to private field laboratories
• Suriname at 52: selling everything for a solo expedition into the rainforest
• Vandalized after death: the fake caterpillars that smeared her, and the 90+ species Linnaeus classified from her drawings