1. On August 18, 1774, a group of Maryland colonists held a meeting in Annapolis to discuss their grievances against British rule. This meeting helped lay the groundwork for the First Continental Congress, which would convene a few months later.

2. On August 18, 1856, abolitionist John Brown led a raid on a settlement in Kansas that was pro-slavery. The raid escalated tensions between pro-slavery and anti-slavery forces in the region and helped set the stage for the American Civil War.

3. On August 18, 1862, the Battle of Cedar Mountain took place in Culpeper County, Virginia. This battle involved forces from Maryland and was part of the larger American Civil War. The Union victory in this battle helped set the stage for the Battle of Antietam, which would take place a few weeks later.

4. On August 18, 1937, a group of workers at the Bethlehem Steel Plant in Baltimore went on strike to protest poor working conditions and low wages. This strike was part of a larger wave of labor activism that swept the country during the Great Depression.

5. On August 18, 1974, President Richard Nixon resigned from office in the wake of the Watergate scandal. Maryland played a key role in this scandal, as many of the key players were based in the state or had connections to it. Nixon's resignation marked the end of a tumultuous chapter in American history.