On April 22, 1864, Congress authorized the use of the phrase “In God We Trust” on U.S. coins.

In 1915, the first full-scale use of deadly chemicals in warfare took place as German forces unleashed chlorine gas against Allied troops at the start of the Second Battle of Ypres in Belgium during World War I.

In 1952, an atomic test in Nevada became the first nuclear explosion to be shown on live network television.

In 1970, millions of Americans concerned about the environment observed the first “Earth Day.”

In 1994, former President Richard M. Nixon died at a New York hospital four days after a stroke.

In 2004, Army Ranger Pat Tillman, who had traded in a multi-million-dollar NFL contract to serve in Afghanistan, was killed by friendly fire; he was 27.