"A massive earthquake of divine proportions happens. Your entire civilization has been wiped out by it. You lose..."
Hmm, I wonder if that could be a rare event. Or maybe Godzilla attacks or a huge meteor slams into the Earth, killing almost everyone unless a World Project of a Anti Meteor Missile is built
Better yet it knocks everyone back to the stone age. Each player is left with 2 or 3 cities of pop 3 max, lose all techs except for stone age and the year is now 3000 bc again. All destroyed cities become tribal villages. etc.