Complex sentence: The sexual revolution (also known as a time of "sexual liberation") was a social movement that challenged traditional codes of behavior related to sexuality and interpersonal relationships throughout the Western world from the 1960s into the 1970s.
Split into simpler sentences: The sexual revolution (also known broadly as a time of "sexual liberation") was a social outlook that challenged traditional codes of behaviour related to sexuality and interpersonal relationships. The phenomenon took place throughout the Western world from the 1960s into the 1970s.