You probably know most pianos have two or three pedals. Two is the norm; one for sustain and the other for softer playing. But have you ever seen a piano with a full pedal keyboard, as in the picture below?

Unlike an organ, say, the pedals on a pedal piano usually activate the lowest strings. In other words, you can play the lower notes using your feet instead of your fingers, leaving you free to play "more" notes than usual.

To see a larger picture of the pedal piano, click on this link.