Whoopie! We're all gonna pay?

As the crisis in Iraq unfolds, it's worth thinking about the tremendous cost of fighting. The loss of life is the most devastating price, but the loss of all the productive things that could have been done with the money ? from teaching our children to repairing our infrastructure to giving our seniors a bit of security after a life of hard work ? is nothing short of catastrophic.

Here's a look at some of the mind-blowing costs of war.

1. Most expensive war ever fought: World War II (1941-1945).

Coming in at somewhere between $4 and $5 trillion, the second World War tops every other war ever fought in U.S. history for its incredible expense. (It also wins the prize for number of humans slaughtered and number of nations involved.)