Dog attack deaths and maimings
2013: An EF5 tornado strikes Moore, Okla., killing 24 people -- including seven students at Plaza Towers Elementary school. The tornado injured another 377 people and caused an estimated $2 billion in damage.
Vasco da Gama arrives in India, Christopher Columbus dies, Norman Rockwell makes his Saturday Evening Post cover debut, HIV is discovered, and "Cheers" airs its series finale, all on this day.
Master Sgt. Nathaniel Cosby was convicted of murder, obstructing justice and attempting to patronize a prostitute as his court-martial wrapped up on Thursday.