Included in the NYPL's recent addition to the Flickr Commons project is Changing New York, a selection of photos taken of NYC in the 1930s by Berenice Abbott as part of a government program for unemployed artists. Here are the Starrett-Lehigh Building and looking north from Washington Square...so open! And the buildings are so low too. The Cyanotypes of British Algae set is worth a look as well.