As the U.S. marks the 250th anniversary of the Battle of Bunker Hill, it might take a moment — or more — to remember why. Start with the very name. Prize-winning historian Nathaniel Philbrick says: “There’s something percussive about it: Battle of Bunker Hill.” Much of the world looks to the Battle of Lexington and Concord, fought on April 19, 1775, as the start of the American Revolution. But many scholars cite Bunker Hill and June 17 as the real beginning, the first time British and rebel forces faced off in sustained conflict over a specific piece of territory. A day-long reenactment of the battle got underway Saturday morning with the seaside city of Gloucester standing in for Charlestown. Organizers chose a state park some 35 miles (56 kilometers) from Boston to stage the battle because such activity is prohibited at the actual site. Hundreds of onlookers watched as sharpshooters positioned on a rocky outcropping fired upon red-coated British sailors landing in the harbor. During the actual battle, British soldiers responded by setting a fire to drive them off and used the smoke to mask their movements. Bunker Hill was an early showcase for two long-running themes in American history — improvisation and how an inspired band of militias could hold their own against an army of professionals.