Most have heard the story of accidental discovery of penicillin by Alexander Flemming in a discarded culture (Petri) dish left in a window in his lab at St. Mary's Hospital, London. The chance observance (1928) is a well-noted example of “serendipity” in research. The discovery went nowhere, however until Flemming's 1929 publication was remembered in 1938 by Howard Florey and Ernst B. Chain at Oxford, who developed a method to extract and purify the first “antibiotic”. Initial production at the start of World War II used buckets, bathtubs, milk bottles, and any number of items resembling a common laboratory synthesis flask. Needless to say, this did not meet the wartime demand. A top-secret project was initiated in the US in mid-1943 via a consortium of industry and academic partners, including Shell Development Company, to scale up production. This led to rapid development of a 100-m3 mechanically stirred bioreactor, the first of its kind. Scale-up and production was sufficient to provide the full supply needed to support the Allies D-Day invasion of Normandy one year later (1944). This achievement ranks as one of the great success stories in chemical engineering and process development.