Hip-hugger bell-bottom jeans were de rigueur for college women in 1972, as were beards and long locks for ­college men (note the onlookers). Bare feet also were very “in,” weather permitting. Archivists say these unidentified students were performing in “To Dance Is To Live,” which began in 1970 as an Earth Day celebration held on Poe Field. Ze’eva Cohen, who created ­Princeton’s dance program, repeated “To Dance Is To Live” in subsequent years, making this 1972 performance her third annual springtime dance event. Do any PAW readers recognize themselves as performers or in the crowd?