File:National Jewish Hospital2.jpg
Taken between 1920 and 1940(?)
http://photoswest.org/cgi-bin/imager?10028623+X-28623
It is likely that this photograph was first published without a copyright notice, as was usual for photographs at the time (and no copyright notice is visible on the source). If so, this image was never copyrighted. If it was copyrighted, the copyright was never renewed, as an exhaustive search here reveals.