Event was (and still is) celebrated in USSR (Russia) since 1962 as "Day of Cosmonautics", from 2001 to 2022 as "Yuri's Night" in US (https://futurism.com/space-conference-censors-yuri-gagarin) and since 2017 as "International Day of Human Space Flight" by the UN.

Pictured: Yuri Gagarin with daughters Galya & Lena, and Ira Komarova. 1965, New Year's Eve.