PHOTO: Deepwater Horizon oil spill (BP oil spill) off the Gulf of Mexico.
Today's Highlights in History:
On April 20, 1977, the U.S. Supreme Court, in Wooley v. Maynard, ruled 6-3 that car owners could refuse to display state mottoes on license plates, such as New Hampshire's "Live Free or Die."
The Woody Allen comedy "Annie Hall," co-starring Diane Keaton in the title role, went into general release.
On this date: In 1792, France declared war on Austria, marking the start of the French Revolutionary Wars.
In 1861, Col. Robert E. Lee resigned his commission in the United States Army. (Lee went on to command the Army of Northern Virginia, and eventually became general-in-chief of the Confederate forces.)
In 1889, Adolf Hitler was born in Braunau am Inn, Austria.
In 1912, Boston's Fenway Park hosted its first professional baseball game while Navin Field (Tiger Stadium) opened in Detroit. (The Red Sox defeated the New York Highlanders 7-6 in 11 innings; the Tigers beat the Cleveland Naps 6-5 in 11 innings.)
In 1914, the Ludlow Massacre took place when the Colorado National Guard opened fire on a tent colony of striking miners; about 20 (accounts vary) strikers, women and children died.
In 1916, the Chicago Cubs played their first game at Wrigley Field (then known as Weeghman Park); the Cubs defeated the Cincinnati Reds 7-6.
In 1947, Denmark's King Christian X, a popular symbol of resistance to German occupation during World War II, died at age 76, ending a reign of 35 years.
In 1968, Pierre Elliott Trudeau was sworn in as prime minister of Canada.
In 1972, Apollo 16's lunar module, carrying astronauts John W. Young and Charles M. Duke Jr., landed on the moon.
In 1987, the United States deported Karl Linnas to the Soviet Union, where he had been convicted in absentia of Nazi war crimes and faced a death sentence. (Linnas, who maintained his innocence, died of heart disease in Leningrad the following July.)
In 1999, the Columbine High School massacre took place in Colorado as two students, Eric Harris and Dylan Klebold, shot and killed 12 classmates and one teacher before taking their own lives.
In 2010, an explosion on the Deepwater Horizon oil platform, leased by BP, killed 11 workers and caused a blow-out that began spewing an estimated 200 million gallons of crude into the Gulf of Mexico. (The well was finally capped nearly three months later, on July 15.)
Ten years ago: The family of Virginia Tech gunman Seung-Hui Cho (sung-wee joh), who shot and killed 32 people and himself, told The Associated Press they felt "hopeless, helpless and lost," and "never could have envisioned that he was capable of so much violence." A disgruntled worker, William Phillips, shot and killed NASA employee David Beverly at the Johnson Space Center in Houston before barricading himself with a hostage and then killing himself. (The second hostage escaped with minor injuries.)
Five years ago: A judge ruled that George Zimmerman could be released on $150,000 bail while he awaited trial on a charge of murdering 17-year-old Trayvon Martin during a Feb. 2012 confrontation in a Sanford, Florida gated community. (Zimmerman was acquitted.) In Pakistan, a Bhoja Air Boeing 737-200 crashed while on approach to the main airport in Islamabad, killing all 127 people on board.
One year ago: Five former New Orleans police officers pleaded guilty to lesser charges in the deadly shootings on the Danziger Bridge in the days following Hurricane Katrina in 2005.
ESPN fired former Red Sox pitcher Curt Schilling as a baseball analyst after comments he'd made on Facebook that were critical of transgender rights.
Treasury Secretary Jacob Lew announced that Harriet Tubman, an African-American abolitionist born into slavery, would be the new face on the $20 bill, replacing President Andrew Jackson.
Pro wrestler Chyna (Joan Marie Laurer) was found dead in her Redondo Beach, California, apartment; she was 46.