world wars

WHAT CREATES A WORLD WAR:
I believe a world war can be started over many things including oil, money, territory etc. World War 1 was started over the assassination of Ferdinan. It needs more than one allie for both saides and it would take alot of money from the countries invovled.
WHAT WOULD CREATE ONE TODAY:
Today things are much more complicated. it can start just from politics. For us to enter a world war it would probrably take nuclear threats, the invasion of Isreal, or another 911. I think it would take more than either WW1 or WW2 because since we've expierienced them, we're smarter and know possible outcomes.