Couple sunbathing on a sunny beach

This picture shows a couple sunbathing on a sandy beach in the sun. The other towels laying on the beach next to them suggest that they are not alone but their companions have possibly gone for a swim. I noticed there are a pair of sunglasses in the sand near the girl's feet - I wonder if they were picked up or if they got lost.

The date of the picture is unknown but the plastic mounted slide is similar to others I have where the content suggests 1960s. The location as well is not known and there are not many clues in the picture which allow it to be easily pinned down.