Former Pittsburgh Steelers defensive lineman L.C. Greenwood waving to fans in 2006. He died Sunday at the age of 67. Stephen M. Gross /UPI /Landov hide caption

itoggle caption Stephen M. Gross /UPI /Landov

Joy Covey, then the chief financial officer of, on the floor of the Chicago Board Options Exchange in 1997, the year Amazon went public. She was with exchange Vice Chairman Thomas Ascher (left) and CEO William Brodsky. John Zich/Chicago Board Options Exchange/AP hide caption

itoggle caption John Zich/Chicago Board Options Exchange/AP

Virginia Johnson and her then-husband, William Masters, in 1972. They studied sexual behavior for decades. She died this week in St. Louis. Masters died in 2001. AP hide caption

itoggle caption AP

This early version of the mouse (named for its tail-like cord) was assembled by Douglas Engelbart and his Stanford team in 1963. Getty Images/Life hide caption

itoggle caption Getty Images/Life