By The Associated Press

Today is Friday, Feb. 28, the 59th day of 2020. There are 307 days left in the year.

Today’s Highlight in History:

On Feb. 28, 1953, scientists James D. Watson and Francis H.C. Crick announced they had discovered the double-helix structure of DNA.

On this date:

In 1844, a 12-inch gun aboard the USS Princeton exploded as the ship was sailing on the Potomac River, killing Secretary of State Abel P. Upshur, Navy Secretary Thomas W. Gilmer and several others.

In 1917, The Associated Press reported that the United States had obtained a diplomatic communication sent by German Foreign Minister Arthur Zimmermann to a German official in Mexico proposing a German alliance with Mexico and Japan should the U.S. enter World War I. (Outrage over the telegram helped propel America into the conflict.)

In 1942, the heavy cruiser USS Houston and the Australian light cruiser HMAS Perth were attacked by Japanese forces during the World War II Battle of Sunda Strait; both were sunk shortly after midnight on March 1 with a total loss of more than 1,000 men.

In 1975, 42 people were killed in London’s Underground when a train smashed into the end of a tunnel.

In 1983, the long-running TV series “M-A-S-H” ended after 11 seasons on CBS with a special 2 1/2-hour finale that was watched by an estimated 121.6 million people.

In 1988, the 15th Olympic Winter Games held its closing ceremony in Calgary, Alberta.

In 1993, a gun battle erupted at a religious compound near Waco, Texas, when Bureau of Alcohol, Tobacco and Firearms agents tried to arrest Branch Davidian leader David Koresh on weapons charges; four agents and six Davidians were killed as a 51-day standoff began.

In 1996, Britain’s Princess Diana agreed to divorce Prince Charles. Their 15-year marriage officially ended in August 1996; Diana died in a car crash in Paris a year after that.

In 2005, In Santa Maria, California, the prosecution and defense gave opening statements in the sexual molestation trial of Michael Jackson, who was later acquitted.

In 2013, Benedict XVI became the first pope in 600 years to resign, ending an eight-year pontificate. Benedict was succeeded the following month by Pope Francis.

In 2014, delivering a blunt warning to Moscow, President Barack Obama expressed deep concern over reported military activity inside Ukraine by Russia and warned “there will be costs” for any intervention.

In 2018, Walmart announced that it would no longer sell firearms and ammunition to people younger than 21 and would remove items resembling assault-style rifles from its website. Dick’s Sporting Goods said it would stop selling assault-style rifles and ban the sale of all guns to anyone under 21.

Ten years ago: Sidney Crosby scored the winning goal in overtime to give Canada a 3-2 victory over the United States in the final event of the Vancouver Olympics. Canada earned its 14th gold medal, the most by any country at any Winter Olympics. The American silver was the 37th medal won by the United States at these games, also the most by any country at any Winter Olympics.

The U.S. won the medals race for the first time since 1932.

Five years ago: Venezuelan President Nicolas Maduro announced his country would shrink the size of the U.S. Embassy staff, limit the activities of U.S. diplomats and require American tourists to apply for visas, saying that “gringo” meddling had forced him to adopt the series of restrictive measures. An Egyptian court declared Hamas a “terror organization,” further isolating the rulers of the Gaza Strip. Death claimed NFL player and coach Tom Bettis at age 81; baseball player Alex Johnson at age 72; and basketball player Anthony Mason at age 48.

One year ago: Talks between President Donald Trump and North Korea’s Kim Jong Un collapsed after the two sides failed to bridge a standoff over U.S. sanctions.