Please see these prior posts from yours truly: here, here, and here.
I hope to have another celebratory post up later in the day.
Update: It’s now clear that my post won’t make it up today so it will be a belated May Day post. The topic? An introduction to KOR, the Workers’ Defense Committee (later: Komitet Samoobrony Społecznej, Social Self-Defense Committee/KOR, KSS-‘KOR’) in Poland that played a direct “service” role in the emergence of Solidarity (or Solidarność, the first non-Communist party-controlled trade union in the Warsaw Pact countries) in 1980.