1. In 1775, the first shots of the Revolutionary War were fired in Lexington and Concord, Massachusetts on April 19. This day is now known as Patriots' Day in Massachusetts and is celebrated with reenactments and parades.

2. Also on April 19, but in 1897, the first Boston Marathon was held. It has since become one of the most famous marathons in the world, attracting elite runners from around the globe.

3. On April 19, 1912, the Massachusetts Board of Education passed a law requiring all public schools to provide physical education as part of their curriculum. This law helped to promote the importance of physical fitness in children.

4. In 1960, the Boston Celtics won their first NBA championship on April 19, defeating the St. Louis Hawks. This was the first of 17 championships for the storied franchise.

5. Finally, on April 19, 1995, a truck bomb exploded outside the Alfred P. Murrah Federal Building in Oklahoma City, killing 168 people, including three from Massachusetts. This tragic event led to increased security measures at many government buildings and public spaces in Massachusetts and beyond.