When and What:  I am guessing in the 1920's The Bathing Beach at the Hotel Del Otero in Spring Park on Lake Minnetonka. Notice that a majority of the men are wearing black full torso type bathing suits which were common in the late 1800's and early 1900's. They don't appear to extend down very far which would imply they are the newer ones. Notice all the swimming 'toys' in use. Things which were normally found at beaches. Things like diving platforms (to the upper right), and water wheels (upper left), small platforms to sit on which would allow your feet to dangle in the water, and provide a place for kids to learn to dive, (also upper left). What the object is in the upper left that resembles a large pipe, is beyond me, but I am sure it was fun. The device that passes between the barrels marked "DANGER" was really a blast. It was a slide with tracks in it, some times refered to as a "roller coaster". You would sit on this small platform with rollers on it and shoot down this slide and into the water. In this picture you can see the white water produced by the most recent "arrival" from the slide. While I never used this beach, as a kid I used several others having the same amenities and will never forget how much fun they were.