Check out this live performance from 1970. Chicago performs their hit 25 Or 6 To 4 live.
The amazing thing about this video is what lead guitarist Terry Kath does during the guitar solo. It takes a little while for him to get going, but it’s soooooo worth the wait!
His epic guitar solo kicks in at the 3 min mark of the video (and it lasts for almost 2 and 1/2 mins.)