This could be me! I think of "me" each time I look at it. It is dated 5/30/67 and was taken evidently at Mystery Forest, Angola, Indiana, 3.5 miles North on US 27 and it says it is demonstrating the weird powers of gravity. It is a postcard.
Why me? Because of the dress. She has on a matched pant suit, keds with no socks, and has a short hairdo (black hair which I once had....sigh....) that was popular at the time. I can't tell if it is double knit but double knit was wonderful! No iron, never wrinkle fabric that everyone adored.
But what is she demonstrating. I googled Mystery Forest and gravity and have found no answer. One of the Sleuths (Don Thompson) can probably tell us exactly what was going on. But isn't it an interesting old postcard?