What is a maypole?

I remember as a child 50 years aoo, several of us would attach different color ribbons to the top of a pole and we would walk around the pole holding a ribbon, wrapping the pole in many colors. Its done on May 1st, "May Day," to signify unity of working people. Its history can be found at http://www.geocities.com/capitolhill/5202/mayday.htm