Sub-prime mortgages were the TIP of the iceburg that sank this titanic.
The first, in a looooong line of dominoes, if you will.
What crashed the entire modern world, what required billions in bailouts, were the TRILLIONS in bets hedged on those loans. IE, dirivatives. People bet money they didn't have, that these loans would be payed off. The loans were not payed off. The people didn't have the money to cover their losses. This is why they needed to be bailed out. You have to understand, we are talking about more money than is in actual "existence". Not just as printed money...but EXISTING money. The amounts wagered exceeded the total amount of liquidated assests of every man, woman, and child in the US, and much of the world. In other words, they were betting in make believe dollars, but with the intention of getting real pay outs. If any of this sounds familiar, it's because the very same thing caused problems prior to the great depression. In essence, our "roaring 90s" finally came to it's inevitable end.