OS X Mavericks extra desktops (spaces) opening seemingly randomly

I don't often use mission control, or extra desktops (spaces). Every so often, I do open mission control by mistake, and I have dozens of spaces showing at the top of the screen.

Is there a shortcut key or something that I am pressing accidentally in my workflow that is opening them? A google search doesn't show anything obvious. Is there a way I can prevent them from being opened at all?