On April 22, 2005, Zacarias Moussaoui pleaded guilty in a federal courtroom outside Washington, D.C., to conspiring with the Sept. 11 hijackers to kill Americans. (Moussaoui is serving a life prison sentence.)

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

In 1889, the Oklahoma Land Rush began at noon as thousands of homesteaders staked claims.

In 1898, with the United States and Spain on the verge of war, the U.S. Navy began blockading Cuban ports. Congress authorized creation of the 1st U.S. Volunteer Cavalry, also known as the “Rough Riders.”

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; thousands of soldiers are believed to have died.

In 1937, thousands of college students in New York City staged a “peace strike” opposing American entry into another possible world conflict.

In 1952, an atomic test in Nevada became the first nuclear explosion shown on live network television as a 31-kiloton bomb was dropped from a B-50 Superfortress.

In 1954, the publicly televised sessions of the Senate Army-McCarthy hearings began.

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

In 1994, Richard M. Nixon, the 37th president of the United States, died at a New York hospital four days after suffering a stroke; he was 81.

In 2000, in a dramatic pre-dawn raid, armed immigration agents seized Elian Gonzalez, the Cuban boy at the center of a custody dispute, from his relatives’ home in Miami; Elian was reunited with his father at Andrews Air Force Base near Washington.

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

Today’s Birthdays: Actor Estelle Harris is 93. Actor Jack Nicholson is 84. Author Janet Evanovich is 78. Movie director John Waters is 75. Singer Peter Frampton is 71. Actor Sheryl Lee is 54. Rock musician Shavo Odadjian (System of a Down) is 47. Actor Michelle Ryan is 37. Actor Amber Heard is 35.