In October 1965, the Rolling Stones played two shows on the same day at the Odeon Theatre in Glasgow, at the height of the British Invasion. That day brought an unexpected visitor backstage: Joan Baez, the queen of folk and protest music, stopped by to say hello to a band that represented almost the opposite of her musical world. Backstage, Baez ran into Mick Jagger and the rest of the band, and amid laughter, they ended up posing together for a series of photos that would come to symbolize a curious intersection of two worlds of ’60s rock. In the photos, while everyone was making faces and joking around for the camera, Charlie Watts was the only one who remained serious, with that aloof and elegant demeanor that always characterized him, even in the midst of the rock ’n’ roll circus.