Accidently did "Mission Control" or "Expose" on Windows 8

Mission Control/Expose is a function of MacOS and Ubuntu where it throws all open programs' Windows up on the screen like this. I'm aware that this can be done with Windows. I'm also aware of the (Alt+tab) and (Windows+Tab) to cycle through programs and that this can also be done on Windows7.

What's bothering me is how. I accidently did something while reaching over at something on the table. The mouse was on my laptop and I don't know what got pressed but it did exactly this...

I was wondering if anyone had any idea what the shortcut keys are for this.