June 23, 1931

1931Gunnar Uusi, Estonian chess player (died 1981)^[†]

Gunnar Uusi was an Estonian chess player who won the Estonian Chess Championship six times.

1931Ola Ullsten, Swedish politician and diplomat (died 2018)^[†]

Stig Kjell Olof "Ola" Ullsten was a Swedish politician and diplomat who was Prime Minister of Sweden from 1978 to 1979 and leader of the Liberal People's Party from 1978 to 1983. He also served as Deputy Prime Minister briefly in 1978 and then again from 1980 to 1982 and served as Minister for Foreign Affairs from 1979 to 1982. Ullsten is Sweden's only Liberal prime minister since the 1930s.

1931Wiley Post and Harold Gatty take off from Roosevelt Field, Long Island in an attempt to circumnavigate the world in a single-engine plane.^[†]

Wiley Hardeman Post was an American aviator during the interwar period and the first pilot to fly solo around the world. Known for his work in high-altitude flying, he helped develop one of the first pressure suits and discovered the jet stream. On August 15, 1935, he and American humorist Will Rogers were killed when his aircraft crashed on takeoff from a lagoon near Point Barrow in the Territory of Alaska.