Today is Friday, Aug. 20, the 232nd day of 2021. There are 133 days left in the year.

Today’s Highlight in History:

On August 20, 1968, the Soviet Union and other Warsaw Pact nations began invading Czechoslovakia to crush the “Prague Spring” liberalization drive.

On this date:

In 1862, the New York Tribune published an open letter by editor Horace Greeley calling on President Abraham Lincoln to take more aggressive measures to free the slaves and end the South’s rebellion.

In 1866, President Andrew Johnson formally declared the Civil War over, months after fighting had stopped.

In 1953, the Soviet Union publicly acknowledged it had tested a hydrogen bomb.

In 1955, hundreds of people were killed in anti-French rioting in Morocco and Algeria.

In 1964, President Lyndon B. Johnson signed the Economic Opportunity Act, a nearly $1 billion anti-poverty measure.

In 1979, swimmer Diana Nyad succeeded in her third attempt at swimming from the Bahamas to Florida.

In 1986, postal employee Patrick Henry Sherrill went on a deadly rampage at a post office in Edmond, Okla., shooting 14 fellow workers to death before killing himself.

In 1988, a cease-fire in the war between Iraq and Iran went into effect.

In 1989, fifty-one people died when a pleasure boat sank in the River Thames (tehmz) in London after colliding with a dredger.

In 2017, actor, comic and longtime telethon host Jerry Lewis died of heart disease in Las Vegas at the age of 91.

In 2019, President Donald Trump abruptly canceled an upcoming trip to Denmark, which owns Greenland, after the Danish prime minister dismissed the idea of the United States purchasing the mostly frozen island.

Today’s Birthdays: Boxing promoter Don King is 90. Former Sen. George Mitchell, D-Maine, is 88. Former U.S. Rep. Ron Paul, R-Texas, is 86. Former MLB All-Star Graig Nettles is 77. Broadcast journalist Connie Chung is 75. Rock singer Robert Plant (Led Zeppelin) is 73. Country singer Rudy Gatlin is 69. Singer-songwriter John Hiatt is 69. Actor-director Peter Horton is 68. TV weatherman Al Roker is 67. Actor Brant Daugherty is 36. Actor-singer Demi Lovato is 29.