1. In 1635, celebrated Puritan leader Roger Williams was banished from Massachusetts Bay Colony for his liberal beliefs and challenging orthodox authorities. Williams went on to found the colony of Rhode Island, known for its religious tolerance, and helped shape the development of the United States' commitment to freedom of conscience.

2. April 23, 1775, also known as the "Shot Heard 'Round the World," marked the beginning of the Revolutionary War, when the first shots were fired between colonial militiamen and British soldiers at the Battle of Lexington and Concord.

3. In 1977, John F. Kennedy Library was dedicated in Boston, honoring the life and legacy of the 35th President of the United States, who famously represented Massachusetts in the U.S. Senate before assuming the presidency in 1961.

4. April 23, 1990, saw the groundbreaking ceremony for the Big Dig, a massive engineering project aimed at replacing the aging elevated highway system that ran through downtown Boston with a modern underground system. The project, completed in 2007, cost an estimated $14.8 billion and was one of the most expensive public works projects in American history.

5. In 2013, the city of Boston was rocked by the bombing of the Boston Marathon, which killed three people and injured more than 260 others. Two brothers, Dzhokhar and Tamerlan Tsarnaev, were later identified as the perpetrators, with Tamerlan killed in a shootout with police and Dzhokhar captured and sentenced to death. The tragedy brought the city together in grief and resolve, with the slogan "Boston Strong" becoming a rallying cry for resilience and community.