I've just watched this short film, you really really should too.
Levi Bettwieser from Boise, Idaho has started up a project where he collects old discarded and undeveloped film rolls. He finds them in thrift stores and garage sales,on their own, in boxes and even inside old cameras. It's a herculean task. He's developed 5000+ images and has a 1000 rolls still waiting. The video deals with a cigar box of 31 rolls of film that when developed were never before seen images from WW2.
The projects Instagram feed has a pile of other found images and is definitely worth a follow. You can read an interview Levi did with VICE here. I'll share a few images below but really click the links and check the rest out. Old images without context are everything I love and I love everything about this project, completely up my alley.