On this date in history:
In 1787, with George Washington presiding, the first regular session of the Constitutional Convention, which drew up the Constitution of the United States, convened at Independence Hall in Philadelphia.
In 1878, H.M.S. Pinafore, an operetta by Gilbert and Sullivan, opened in London.
In 1925, John Scopes was arrested for teaching evolution in a Tennessee high school, leading to a trial that became a media sensation. Scopes was convicted and fined $100; the conviction was later overturned.
In 1935, winding up his legendary career (with the Boston Braves in his last season), Babe Ruth hit his 714th home run in his final game. The record stood for 39 years until Hank Aaron, also with the Braves, although in Atlanta, broke it in 1974. Aaron went on to hit 755 homers and current record-holder Barry Bonds had 762.
In 1977, the first installment of George Lucas' Star Wars film series was released.
In 1986, 5 million people formed a broken 4,000-mile human chain from Los Angeles to New York in "Hands Across America," to benefit the nation's homeless. The event raised $24.5 million.
In 1994, after living 20 years in exile, mostly in the United States, Russian author Alexander Solzhenitsyn returned to his homeland. He had been expelled after The Gulag Archipelago, an expose of the Soviet prison camp system, was published in the West in 1974.
In 1997, mutinous soldiers seized power in Sierra Leone.
In 2008, NASA's Phoenix spacecraft made a smooth landing on Mars, completing a nine-month, 422 million-mile journey, setting down in the planet's frigid polar region where scientists hoped to find water.
In 2009, despite international warnings, North Korea reported it had launched a second nuclear missile test, with officials saying they were only boosting self-defense capabilities.
In 2012, private space company SpaceX's Dragon capsule became the first commercial cargo vessel to visit the International Space Station.
In 2013, amid tight security, about 3,000 people who had been in the Boston Marathon April 15 when bombs killed three people and injured scores of others returned to complete the final mile. One runner said the event, called OneRun, was "a great way to show the strength of Boston and the camaraderie in our city."
In 2017, Facebook founder and CEO Mark Zuckerberg received an honorary degree from Harvard, 12 years after dropping out of the ivy league school. Actors Judi Dench and James Earl Jones, and composer John Williams also were honored.