Sep 28,1928 – Scottish biologist and pharmacologist Alexander Fleming  noticed a bacteria-killing mold growing in his laboratory, discovering what became known as penicillin.

In 1999, Time Magazine named Fleming one of the 100 Most Important People of the 20th Century for his discovery of penicillin, and stated:

It was a discovery that would change the course of history. The active ingredient in that mould, which Fleming named penicillin, turned out to be an infection-fighting agent of enormous potency. When it was finally recognised for what it was, the most efficacious life-saving drug in the world, penicillin would alter forever the treatment of bacterial infections. By the middle of the century, Fleming’s discovery had spawned a huge pharmaceutical industry, churning out synthetic penicillins that would conquer some of mankind’s most ancient scourges, including syphilis, gangrene and tuberculosis.