Blue plaques on buildings in the UK mark places where important people
lived or important things happened.
The one on the red brick wall just behind me celebrates the birth of the age of antibiotics.
I'm not outside St Mary's Hospital in London,
where Alexander Fleming famously observed the lethal effects of penicillium mould
on cultures of bacteria almost 100 years ago.
Rather, I'm outside the Dunn School of Pathology in Oxford, where a decade later.
Ernst Chain, Howard Florey and colleagues less famously turned
that observation into a lifesaver for medicine.
Or, as it says on the plaque, in this building,
Howard Florey, Ernst Chain, Norman Heakley and colleagues first isolated and purified penicillin
for the treatment of bacterial infection, 1938 to 1941.
Antibiotics have saved countless millions of lives since.
But bacterial infections are constantly fighting back.
I'm Roland Pease, and in the next three episodes of Discovery from the BBC World Service,
I 'll be hearing why health professionals worldwide are alarmed at the waning power of existing antibiotics
and the struggle to find new compounds to stock the pharmacy shelves.
But first, let 's go inside the Dunn School and hear what happened here
in 1940 and why the lessons from then.
Still live on.