January 2 » American statesman and diplomat John Hay announces the Open Door Policy to promote trade with China.
February 14 » British forces begin the Battle of the Tugela Heights in an effort to lift the Siege of Ladysmith.
May 17 » The children's novel The Wonderful Wizard of Oz, by L. Frank Baum, is first published in the United States. The first copy is given to the author's sister.
May 22 » The Associated Press is formed in New York City as a non-profit news cooperative.
October 25 » The United Kingdom annexes the Transvaal.
December 14 » Quantum mechanics: Max Planck presents a theoretical derivation of his black-body radiation law.
Day of marriage April 30, 1921
The temperature on April 30, 1921 was between 6.8 °C and 20.2 °C and averaged 13.7 °C. There was 12.0 hours of sunshine (81%). The average windspeed was 3 Bft (moderate breeze) and was prevailing from the northeast. Source: KNMI
In The Netherlands , there was from September 9, 1918 to September 18, 1922 the cabinet Ruys de Beerenbrouck I, with Jonkheer mr. Ch.J.M. Ruys de Beerenbrouck (RKSP) as prime minister.
January 20 » The British K-class submarine HMS K5 sinks in the English Channel; all 56 on board die.
January 20 » The first Constitution of Turkey is adopted, making fundamental changes in the source and exercise of sovereignty by consecrating the principle of national sovereignty.
March 1 » The Australian cricket team captained by Warwick Armstrong becomes the first team to complete a whitewash of The Ashes, something that would not be repeated for 86 years.
June 15 » Bessie Coleman earns her pilot's license, becoming the first female pilot of African-American descent.
August 28 » The Red Army dissolved the Free Territory, after driving the Black Army out of Ukraine.
October 13 » Soviet republics sign the Treaty of Kars to formalize the borders between Turkey and the South Caucasus states.
When copying data from this family tree, please include a reference to the origin: Hans Weening, "Family tree Weening", database, Genealogy Online (https://www.genealogieonline.nl/stamboom-weening/I136384.php : accessed September 26, 2026), "Harmke Laanstra (1900-)".
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