1. In 1856, the Republican Party of Maine held its first convention in Augusta. This convention was a defining moment in the history of the party, as it set the stage for the party's eventual dominance of Maine politics.

2. On May 21, 1960, the Maine State Lottery was established. This marked the beginning of legal gambling in Maine, and the lottery has since become a significant source of revenue for the state.

3. On May 21, 1901, the Maine Legislature passed a law allowing cities and towns to establish public libraries. This helped Maine residents gain greater access to education and information, and helped shape the state's culture of literacy.

4. On May 21, 1937, the popular diner chain, Howard Johnson's, opened its first restaurant in Maine. Howard Johnson's would go on to become a beloved part of Maine's culinary landscape and an icon of American roadside dining.

5. On May 21, 2014, Maine became the third state in the country to legalize same-sex marriage. This marked a major milestone in the fight for LGBTQ+ rights and helped pave the way for similar legislation in other states.