A Project for Great Grandpa

My mother inherited a box of her grandfather's papers and things.  There are all sorts of treasures in it, but my favorite are the negatives.  My great-grandfather loved taking pictures.  We have negatives of pictures he took from about 1910 up through about 1960.  During these years he traveled a lot.  

We've got pictures from Mississippi, New Orleans, Washington DC, Yale, Salt Lake, North Ogden, Idaho Falls, Yellowstone, Chicago, Nauvoo, New Zealand (I think), and New York.  We've got pictures of missionaries, government workers, poor southern farmers, and fishing buddies.  We've got pictures of horses, buggies, buses, planes, and cars.  And, best of all, we've got pictures of his parents, his wife, some of his siblings and their kids, his children, and some of his grandchildren.  

Philadelphia 1926 ~ Sesquicentennial Celebration

As I have access to the scanner that can digitize these oddly sized negatives, I get the fun of discovering treasures.  And then the detective work begins.  Who are these people?  What are their stories?  And how do they know Grandpa?  And how can I find their families to share these with them?  Amazingly enough, we often figure it out.