Margen
In 1928, a scientist went on holiday without washing the dishes. When he came back, a mould had invaded one of his plates… and had killed the bacteria all around it.
Anyone else would have thrown it in the bin. Alexander Fleming kept staring at it. That mould, Penicillium, was making something that wiped out microbes without touching human cells.
It took more than a decade to become a medicine, but that unwashed plate is called penicillin today, and it is estimated to have saved more than 200 million lives.