Pope Francis (pictured) releases the encyclical Laudato si', in which he calls for action on environmental degradation and climate change. Nine people, including a state senator, are killed in a mass shooting at a church in Charleston, South Carolina. In basketball, the Golden State Warriors defeat the Cleveland Cavaliers to win the NBA Finals. In ice hockey, the Chicago Blackhawks defeat the Tampa Bay Lightning to win the Stanley Cup. Flooding in the Georgian capital, Tbilisi, kills at least nineteen people and releases zoo animals into the streets.June 21: June solstice (16:58 UTC, 2015); Midsummer festivities (Northern Hemisphere); Winter solstice festivals (Southern Hemisphere);World Music Day; Father's Day in various countries (2015); National Aboriginal Day in CanadaReplica of the Manchester Small-Scale Experimental Machine 217 BC Second Punic War: The Carthaginians under Hannibal executed one of the largest military ambushes in history when they overwhelmingly defeated the Romans. 1826 Greek War of Independence: A combined Egyptian and Ottoman army began their invasion of the Mani Peninsula, but they were initially held off by the Maniots at the fortifications of Vergas. 1898 In a bloodless event during the SpanishAmerican War, the United States captured Guam from Spain. 1919 Admiral Ludwig von Reuter scuttled the German High Seas Fleet in Scapa Flow to prevent the ships from being seized and divided amongst the Allied Powers. 1948 The Manchester Small-Scale Experimental Machine (pictured), the world's first stored-program computer, ran its first computer program.