Millie Caldwell

I found several photos in my Dad's belongings after he died. On the back of this photo it says "Millie Caldwell." His high school diploma has a list of names on the back and this must be Mildred N Caldwell. I assume they were on some type of class outing. He graduated from John Wallace Whitmer High School, Toledo, Ohio in 1938.

Was this a school outing? Where was the photo taken?
People in photo include: Mildred N Caldwell