All of them.
What about the modern great thinkers (oh also derided by those mainstream rigid-thinkers, respectfully) who suggest that Planet Earth is about to go though another cycle . . .
Terrence Mckenna's fantastic Novelty Theory cycles to an end in 2012:
Our own Graham's most recent re-print of 'Fingerprints of the Gods' relates his visit to a Hopi elder who confirms the 'end days'.
Gregg Braden talked about this in 1996:
It goes on and on. Louis Pasteur said: "Chance favours the prepared mind"
So much to talk about and only 5 years to do it in.