Too many, too many.......watch the inundation of the Black Sea by the rising waters of the Med (the origin of the Noah's Flood story?) Hang around the city of Ur during a Moon festival about 3000 BC? Visit Carthage before the Romans got medieval on it? Watch Vesuvius do its stuff in 79 AD? Walk round Londinium in about AD 500 and see just what's occurring. Still not enough.
Oh hey, what about hanging about in the crowd for a few days in Roman Jerusalem about 33 AD while some convicts got theirs.....