"South California Purples"
I just love the "Fat" Bass, and the horns/organ/guitar work on this track...
http://www.youtube.com/watch?v=lghDG9vYfRQ
I was lucky to see Chicago in 1972, just before they took off to their pop-commercial era, they were just foraying into it... One of the most satisfying rock shows of the year, for me !! The had perfect sound for that auditorium, something that happens because you make it happen, and not by chance. The highlight of that live show was one of the encore numbers, a jammin' version of "Free".