Crustal Displacement - a physical pole shift. The mechanism is not understood, and most theories are just wild guesses. However it seems quite likely we had one 12,000 years ago, and what goes around, comes around.
Charles Hapgood provided substantial evidence for a pole shift at that time, and Allan and Delair have added to it in their book Cataclysm!: Compelling Evidence of a Cosmic Catastrophe in 9500 B.C. Take into account that Albert Einstein endorsed Hapgood's ideas, and we have something to worry about.
Possibility this century = 6
Possibility in 2012 = 6
Could Ancients Predict It? = 6
TOTAL = 18