1. Maine Becomes a State - On June 1, 1820, Maine officially became the 23rd state to join the United States, as part of the Missouri Compromise. The state's nickname, "The Pine Tree State," refers to the abundance of white pine trees that were used in shipbuilding and lumber industries.

2. First Woman Elected to State Senate - On June 1, 1920, Edith A. Nourse became the first woman elected to the Maine State Senate. Nourse served in the Maine legislature throughout the 1920s, and later went on to become a member of the United States House of Representatives.

3. Tallest Building in Maine Opens - On June 1, 1990, the tallest building in Maine, the KeyBank Tower, opened in Portland. The building stands at 21 stories tall, and is one of the most prominent landmarks in the city.

4. Maine Lobster Festival Begins - On June 1, 1947, the first Maine Lobster Festival was held in Rockland, Maine. The festival has since become an annual event, and draws thousands of visitors from around the world to celebrate the state's most famous seafood.

5. World War II Memorial Dedicated - On June 1, 1995, the Maine World War II Memorial was dedicated in Augusta, Maine. The monument honors the nearly 100,000 Mainers who served in the Second World War, and is one of the most prominent memorials in the state.