The end of the Korean War so I could be friends with my Parents when they were young and just married when my Dad came home from the war and watch them grow up. Then re-live the great '80's when money was not an object and all was great!!! (Even the clothes & hair).
I have to pick just one. I would love to witness the Sermon on the Mound, the Dark Ages, the Renaissance, the colony that attempted settling at Roanoke Island, NC, the antebellum south pre-Civil War, the Gettysburg Address, the roaring 20's, man - there are so many.