In case you missed this when it was announced a couple months ago: NYC puts 875,000 archived photos, images online - NYPOST.com:
The city’s Municipal Archives rolled out a new online site that gives the public access to a treasure trove of 875,000 historic photos of the Big Apple, with some dating back to the mid-1800s.
There are snapshots of Yankee slugger Babe Ruth — chomping on a cigar and signing autographs for fans — and dozens of dramatic black-and- white photos of the city’s bridges under construction.
There also are decades’ worth of photos of the city’s once-bustling and industrial waterfront.
Below are a handful of pics that accompanied the NYPost article. What would be cool is if these were all geo-tagged, and then fed into a mobile app. Imagine walking around the city and being able to pull up photos that would give you a view of what your immediate vicinity looked like 100 years ago—a historical slant on augmented reality.