1861, start of the American Civil War. Confederate forces fire on the Union garrison at Fort Sumter in Charleston, South Carolina, fighting between the North and South lasts 4 years with more than half a million deaths.

1961, Soviet cosmonaut, Yuri Gagarin becomes the first man to fly in space, orbiting the Earth once before making a safe landing. And 1981, America's first space shuttle, named Columbia, blasts off from Cape Canaveral, Florida, on its maiden flight. More than two decades later, Columbia meets a tragic end; it disintegrates on reentry killing its 7-passenger crew. And 1947, “my name is Dave Letterman and I am the host of late show, America’s most successful C student.”

David Letterman, the late night TV talk show host is born in Indianapolis.

Today In History, April 12th, Mike Gracia, the Associated Press.