American Civil War: In order to help pay for the war effort, the United States government levies the first income tax as part of the Revenue Act of 1861 (3% of all incomes over US $800; rescinded in 1872).
World War I: The German minelayer SS Königin Luise lays a minefield about 40 miles (64 km) off the Thames Estuary (Lowestoft). She is intercepted and sunk by the British light-cruiser HMS Amphion.
Vietnam War: Operation Pierce Arrow: American aircraft from carriers USS Ticonderoga and USS Constellation bomb North Vietnam in retaliation for strikes against U.S. destroyers in the Gulf of Tonkin.