Births on April 20

Bud Cullen, Canadian judge and politician, 1st Canadian Minister of Employment and Immigration (d. 2005)

Jack Sydney George "Bud" Cullen, (April 20, 1927 – July 5, 2005) was a Canadian Federal Court judge and politician.

10 Jan

Metropolis (1927 film)
Fritz Lang's futuristic film Metropolis is released in Germany.
23 Feb

Uncertainty principle
German theoretical physicist Werner Heisenberg writes a letter to fellow physicist Wolfgang Pauli, in which he describes his uncertainty principle for the first time.
5 May

Virginia Woolf
To the Lighthouse by Virginia Woolf is first published.
27 May

Ford Model T
The Ford Motor Company ceases manufacture of the Ford Model T and begins to retool plants to make the Ford Model A.
26 Jun

Coney Island
The Cyclone roller coaster opens on Coney Island.