" It happened in Chicago in 1886.

On the first of May, strikes paralyzed cities across the country. The Philadelphia Tribune offered a diagnosis: 'The labor element has been bitten by a kind of universal tarantula - it has gone dancing mad.'

Dancing mad were the workers who fought for the eight-hour day and for the right to form unions

...

On every May first, the entire world remembers them. With the passing of time, constitutions, laws, and international accords have proved them right.

But some of the most powerful corporations have yet to find out. They outlaw unions and keep track of the workday with those melting clocks painted by Salvador Dali. "

― Eduardo Galeano , Mirrors: Stories of Almost Everyone