1921-1941 US HISTORY TIMELINE

Warren Harding Presidency

Mar 4, 1921

Warren Harding becomes the 29th president of the United States.

Traffic Lights are Invented

1923

William Potts, a police officer, invents the modern traffic light. It was first installed at a corner in Detroit.

Calvin Coolidge Presidency

Mar 4, 1923

Calvin Coolidge becomes the 30th president of the United States.

Television is Invented

1927

Philo Farnsworth, a simple farmboy, invented and patented the television, changing the way the world would work.

Penicillin is Invented

1928

Dr. Alexander Fleming invented Penicillin while experimenting on the influenza virus and mold. It was not used on a patient until 1943.

Herbert Hoover Presidency

Mar 4, 1929

Herbert Hoover becomes the 31st president of the United States.

Franklin Roosevelt Presidency

Mar 4, 1933

Franklin Roosevelt becomes the 32nd president of the United States.

The Digital Computer is Invented

1937

George Stibitz invented the first digital computer to calculate binary addition.

World War II Begins

Sep 3, 1939

The second world war began when Germany invaded Poland and Great Britain and France declared war on Germany.