A group of German soldiers celebrating their comrade's birthday - World War II 

And what better way to celebrate than with some music performed on an accordion and two violins?

This is a somewhat perplexing photograph - they are obviously in a wooden hut, which has had sheets of newspaper stuck up on part of the walls (possibly as insulation). But is it a barracks hut, or, as I am increasingly beginning to suspect, a POW camp?