I remember bits of a film, probably in the mid-1970s, which seemed to feature a number of young people, mostly girls, in the clothing style of the girls in `Picnic at Hanging Rock’ – very soft focus. They were rowing or being rowed around a lake, and there seemed to be white/marble buildings right on the edge of the lake – looking somewhat Italian. They seemed to sing or chant slowly; `We know a secret we’ll never (ever) tell’.  Can anyone name the film? Thanks in advance!