Abandon Hope All Boys Who Enter Here!      ST link

Original:  Movie Poster for "School For Unclaimed Girls", 1969

Boys go in, but they don't come out! It's like an evil Bikini Beach without the magic.

I've never seen this movie, but the poster reminded me of the St. Trinian's movies. (the 20th century ones) They are funny as all get out, and star Allistair Sims in drag as the headmistress of a VERY wild girls' school. I've included a Wiki link