This song is sung to the tune of “Das Batallion Edgar André” (also known as “Die Freiheit ist unser Gefährte”), as sung by Ernst Busch. I sadly haven’t been bothered to actually look and see if there’s a version of this song on YouTube or so, but there may be; (there is! /skymandr) otherwise, I am sure it can be downloaded or even bought somewhere. It was inspired by a misunderstanding of the original German lyrics: I believed they sang “Das Battalion das ganzen Erde” (“The Batallion of the Entire World”), but it was actually something else, and I thought it was a wasted opportunity to use a phrase that so succinctly sums up what the international brigades were, in a way. Of course, not the whole world, as the conservatives of the day were — and seemingly still are! — content with letting the extreme right do their thing, as long as they don’t kick up too much dust during election campaigns.
Unfortunately, the literal translation of my misunderstanding doesn’t really fit the melody, so I had to restructure it a bit… Notice that the last two lines of the refrain should be sung twice.