cat·a·clysm
Pronunciation: \ˈka-tə-ˌkli-zəm\
Function: noun
Etymology: French cataclysme, from Latin cataclysmos, from Greek kataklysmos, from kataklyzein to inundate, from kata- + klyzein to wash — more at clyster
Date: 1599
1: flood, deluge
2: catastrophe
3a3: a momentous and violent event marked by overwhelming upheaval and demolition; broadly
: an event that brings great changes
— cat·a·clys·mal \ˌka-tə-ˈkliz-məl\ or cat·a·clys·mic \-mik\ adjective
— cat·a·clys·mi·cal·ly \-mi-k(ə-)lē\ adverb

(from the movie Nanking)