Wikipedia:Selected anniversaries/April 3
On April 3:
- 1860 - The first successful Pony Express run was started.
- 1948 - U.S. President Harry Truman signed the Marshall Plan into law.
- 1975 - Bobby Fischer refused to play Anatoly Karpov, giving Karpov the chess title.
- 1986 - IBM unveiled the PC Convertible, their first laptop computer.
- 1996 - Suspected "Unabomber" Theodore Kaczynski was arrested.