This photo is also known as "The falling soldier".
It depicts the death of Federico Borrell Garcia,
a member of the "Lberian Federation of Libertarian Youth" (FIJL),
during the Spanish civil war in the region of Cerro Muriano.
The original photo was taken by the Life Magazine photographer
Capa described how he took the photograph in a 1947 radio interview:
I was there in the trench with about twenty milicianos … I just kind of put my camera above my head and even [sic] didn't look and clicked the picture, when they moved over the trench. And that was all. … [T]hat camera which I hold [sic] above my head just caught a man at the moment when he was shot. That was probably the best picture I ever took. I never saw the picture in the frame because the camera was far above my head
A 2007 documentary, La sombra del iceberg, claims that the picture was staged
Here are some other photos from that same day.
In the first photo you can see Federico Borrell Garcia on the far left side of the group.