Today is a holiday all over the world--except the USA, where it started, according to Wikipedia:
May Day can refer to various labour celebrations conducted on May 1 that commemorate the fight for the eight hour day. May Day in this regard is called International Workers' Day, or Labour Day. The choice of May 1st was a commemoration by the Second International for the people involved in the 1886 Haymarket affair in Chicago, Illinois. As the culmination of three days of labor unrest in the United States, the Haymarket incident was a source of outrage and admiration from people around the globe. In countries other than the United States and Canada, residents sought to make May Day an official holiday and their efforts largely succeeded. For this reason, in most of the world today, May Day has become an international celebration of the social and economic achievements of the labour movement. Although May Day received its inspiration from the United States, the U.S. Congress designated May 1 as Loyalty Day in 1958 due to the day's appropriation by the Soviet Union.[4] Alternatively Labor Day traditionally occurs sometime in September in the United States. Some view this as an effort to isolate American workers from the worldwide community.[5]
UPDATE: Received this email from Agustin Blazquez, the Cuban-American documentary filmmaker:
Today is May 1st, the international day communists celebrate "the workers redemption from exploitation." But in reality it should be known and called as "The International Day of Slave Workers Under Communism." And people all over should demand the end of communism slavery.
My best,
Agustin
Here's a link to a preview of his latest film, about the use of Cuban slave labor in Curacao: