The Unabomber, Ted Kaczynski, is arrested. The mathematician who was driven by anarchist ideas sent out 16 letter bombs between 1978 and 1995, killing 3 people and injuring 23.

The first public mobile telephone call is placed on a Manhattan sidewalk. Motorola's Martin Cooper called Joel Engel of Bell Labs. He later told the BBC that his first words were “Joel, I'm calling you from a 'real' cellular telephone. A portable handheld telephone.”

Harry S. Truman signs the Marshall Plan. $12.4 billion was allocated to help rebuild European economies after the end of World War II and prevent communists from seizing control.

Soviet troops murder about 22,000 Polish nationals. The Katyn massacre is considered the worst massacre of prisoners of war in history. The order to execute all captive members of the Polish Officer Corps was signed by Joseph Stalin.

Gottlieb Daimler patents his engine design. The German engineer's so-called “grandfather clock engine” was lighter than previous four-stroke engines and is considered a milestone for the invention of the automobile.