May Day was once a Germanic pagan holiday- Walpurgisnacht, nowadays it is widely known as a Worker's day, or at least a Workers holiday! As a Workers party - the National Socialists honoured the German worker on this day - and National Socialists from all around the world were also invited to Germany to share in this once pagan celebration!
Many people ignore National Socialism's 'socialist' side, however the National Socialists grew out of the DAP - the German Workers Party and I would encourage everyone to read National Socialism - A Leftwing Movement (link here) and we should never forget this important fact.
Members of the Russian National Socialist Movement
enjoying the May 1st rallies in Berlin 1933
What an irony that today the holiday is plagued by great swathes of unwashed, unemployed students and anarchists, who riot across the cities of Europe - yet claim this as their day - a Workers day!