Hasta el viento tiene miedo (1968)

A group of college students, led by Claudia, decide to investigate a local tower that has figured prominently in disturbing reoccurring dreams Claudia has been having. They are suspended from school for their antics, but Claudia learns from one of the female staff members that the person in the dream is a student who killed herself years before and that the headmistress has seen her ghost.