A recent news article provides information on a three-year project to digitize historical photos of over 10,000 Portland, Maine buildings. The project will be finished in the summer of 2012. Some of the photos are already online and can be found at the following website:
The photos were taken in 1924 for tax purposes. The collection provides a good look at how Portland, Maine appeared in the 1920s. Read more about this story in "Picturing Portland in the digital age", The Portland Press Herald, December 28, 2011.