TIL that the youngest soldier in the first world war (WWI) was an 8 year old from Serbia, Momčilo Gavrić (1 May, 1906 - 28 April 1993)

https://en.wikipedia.org/wiki/Mom%C4%8Dilo_Gavri%C4%87?wprov=sfla1

https://www.reddit.com/r/todayilearned/comments/15r9flw/til_that_the_youngest_soldier_in_the_first_world/