What event did 5 US presidents attend at the same time?

There were two events that 5 US presidents attended at the same time. The first one is the opening of the Ronald Reagan Presidential Library on November 4, 1991. This was also the first time in history that there were 5 presidents together at an event. The presidents were: Nixon, Ford, Carter, Reagan, and the senior Bush. The second time was at the funeral of Richard Nixon on April 27, 1994. The presidents there were: Ford, Carter, Reagan, the senior Bush, and Clinton.