Patriots' Day
A group of re-enactors participate in a parade held on Patriots' Day in Lexington, Mass., April 17, 2017. Patriots’ Day commemorates the opening battle of the American Revolution in 1775. The 2018 holiday will be officially observed April 16, but events will take place in Bedford, Concord and Lexington throughout April. (U.S. Air Force photo by Mark Herlihy)