What Is A Fenderskirt?

Recently we played a gig called 'Car Fun On 21', an Antique Car Show in Libertyville. Between sets we were checking out all the cool cars, and came across this great example of a fenderskirt. So now you know what a fenderskirt is.

As we were posing with the red car, another car drove by with a nice example of fenderskirts. The driver was kind enough to pause for a picture.