did you know that world war 2 was the first ever war where deaths directly caused by the war (like getting bombed or shot) were higher than those caused by disease? for example, in ww1, majority of causalities were due to disease and infections. why this sudden change? all because of the discovery of antibiotics. in the 1920s there was a guy named alexander fleming. this guy liked to grow bacteria for scientific purposes. well, one day he went on holidays and forgot about his bacteria. when he came back he found out his bacteria had grown mold. well, since observing bacteria wasn't enough for him, fleming decided to observe the mold too. when he observed it under a microscope he saw a weird thing: wherever the mold was bacteria had died. this is how penicillin was discovered. yes, penicillin comes from mold, specifically from a type called penicillium mold (the one that grows on old bread). and boom, in ww2 people stopped dying so much from disease cause now they could actually kill the bacteria causing those infections.