Three sets of military-issue boots, under American, French and British flags, march steadily together over a beach, kicking Hitler and Mussolini figures (battered and with bloodied hands) into the sea. The depictions of Hitler and Mussolini are quite vicious, and the artist obviously believed that right was winning over might.
This piece is more than likely referring to the expulsion of Axis forces from North Africa, prior to the Allied assault on Sicily.