Most births at a music concert

Four births – in addition to four well-publicized deaths – were reported by the American Red Cross at the infamous Altamont Speedway (now Altamont Raceway Park) concert headlined by The Rolling Stones in Tracy, California, USA, on 6 December 1969. The chaotic six-hour free concert, which attracted 300,000 revellers, also featured Santana, The Flying Burrito Brothers, Jefferson Airplane (all USA) and Crosby, Stills, Nash & Young (USA/UK/Canada).