New York Yankees vs Toronto Blue Jays July 4, 2010

The number 42 was retired throughout Major League Baseball in honor of Jackie Robinson on April 15, 1997, the 50th anniversary of his breaking the color barrier. The day was declared Jackie Robinson Day, and would later be observed by all of baseball, with select players from every team wearing the number 42. Mariano Rivera, the current closer for the Yankees still wears the number due to a grandfather clause and is the last remaining player to do so. While other teams placed the number 42 with the rest of their retired numbers, the Yankees didn't do so at first. Ten years later, on April 17, 2007, the Yankees honored Robinson by mounting the logo of Jackie Robinson Day with corresponding plaque alongside the rest of the retired numbers.