Unable to close Multiple (!) Safari Windows

When I was out of the room, my cat decided to sit on my Macbook keyboard (it was running) and when I came back, somehow he had managed to open up about 70 Safari windows. This freezes the laptop and I cannot close them or quit Safari, nor even manage to get Safari shut down via force quit. The only thing that works is to shut the compter off with the on/off button. But then, as soon as I reopen Safari, all the windows come flying forth. I have check System, but nothing I've found or done has made any differene.

Suggestions? Thanks!