Luftwaffe honour guards marching with a goose step in a parade in Berlin, date unknown. The goose step is a special marching step performed on formal military parades and other ceremonies. While marching in parade formation, troops swing their legs in unison off the ground while keeping each leg straight and unbent. The step finds its origin back to the Prussian military drill in the mid-18th century. German and Soviet military advisors spread the tradition throughout the world in the 19th and 20th centuries. Apparently, standing on only one leg reminded soldiers of how geese often stand.