Warren Harding president of the USA 1921. Warren Harding dies of an embolism in San Francisco. He had taken ill on 31 Jul 1921.
Calvin Coolidge president of the USA 1921-1929. Calvin Coolidge, vice president under Warren Harding, sworn in as president the day after Harding dies.
Artificial life begins -- the first robot built.
John Larson, a University of California medical student, invented the modern lie detector (polygraph), used by police since 1924.