Map O.1 Use of aggregated cellphone records to track mobility week by week during COVID-19 lockdowns in The Gambia, March–May, 2020 http://bit.do/WDR2021-Map-O_1 ...
World War I involved 32 nations from 1914 to 1919. It redrew the world map and reshaped many borders in Europe. The collapse of the Russian Empire created Poland, the Baltics, and Finland.