What is the longest home run in MLB history?

With Matt Prater setting the all-time NFL record for longest field goal, I think that it is time to see what the longest home run in MLB history is. This record is disputed, since the home run was measured after the fact, but I think that there is enough evidence to declare it the longest in history. This home run was hit by Mickey Mantle on April 17, 1953. The home run was estimated at between 550 and 600 feet. This monumental blast was against the Washington Senators at their home field, Griffith Park. The ball flew out of the park and landed across the street. It was later measured by the Yankees' PR director, Red Patterson. This was a truly monumental home run that will go down in history books for many years.