McDonaldland was created as a marketing campaign in the 1970's to appeal to children, using the same trippy, costumed philosophy as H.R. Pufnstuf. They were so similar in fact that the producers of H.R. Pufnstuf successfully sued McDonald's for infringement.
The characters in McDonaldland include:
Many of the characters such as Mayor McCheese and Officer Big Mac did not last past the 80's, and subsequently in the 2000's the McDonaldland universe concept was essentially abandoned as a marketing concept amid growing concerns over childrens' obesity. Ronald McDonald remains the only character still consistently seen.