4 October

1957: On 4 October 1957, the Soviet Union launched Sputnik 1, the world's first artificial satellite, about the size of a football and taking about 98 minutes to orbit Earth on its elliptical path.

The launch ushered in new political, military, technological, and scientific developments. While the Sputnik launch was a single event, it marked the start of the space age and the 'Space Race' between the USA and the USSR.