Complex sentence: When he was a student in Madrid, he saw a dead woman's hair "growing" from a tomb in the moonlight; the sight made a strong impression on him and he used it in this film some fifty years later.
Split into simpler sentences: When he was a student in Madrid, he saw a dead woman's hair "growing" from a tomb in the moonlight. The sight made a strong impression on him and he used it in this film some fifty years later.