Events on Apr 20

1949
Discovery of Cortisone
The Mayo Clinic announces its discovery of a synthesized hormone, named cortisone, for the treatment of rheumatoid arthritis.

1902
Discovery of Raduim
Marie Curie, Pierre Curie, and Henri Becquerel discover radium.

1841
First Detective Story
The first recognized detective story, Poe's "Murders in the Rue Morgue," is published.