French Quarter history buffs can dig this-- the Historic New Orleans Collection's Vieux Carré Survey is available online. The database includes extensive records of nearly every property within the Quarter, including historical, architectural, legal, and sociological information. The data covers individual lots and structures from the French colonial period to the present.
For the casual researcher, the site makes a "popular searches" tool available that makes it easy to look up common interest locations like Jackson Square, the Beauregard-Keyes House, Cafe du Monde, the French Market, Preservation Hall, Hotel Monteleone, and much more. Results reveal a fascinating combination of materials. Old photos, property summary description, ownership history, insurance paperwork, deeds, maps, illustrations, architectural plans, and much more return.
A few highlights from famous properties:
1866 description of Preservation Hall site: "A lot of ground situated on the two-story brick house No. 72, having on the ground floor two rooms, closet, and cellar; four rooms, gallery and closet in the upper story, with verandah on the street, a two-story brick kitchen of six rooms with balcony, coach-gate, paved yard, water works, shed well, privy, etc."
On the site of present-day Cafe du Monde/French Market in 1804: "Also I am credited with 229 pesos that on Sept. 20 I paid to Urbano Gagnie...to cover the value of 23 stands that he made in the building to be used as a meat and fresh fish market...and 34 pesos for a shed measuring about 60 feet and made of beams and boards to protect from the sun said fish stands ..."
Times-Picayune article on Tujague's in 1981: "Hanging on the wall at Tujague's in the French Quarter is one of the strangest pictures you'll ever see.It's a photo of three bartenders behind the picturesque wooden bar---and no booze on the shelves behind them. 'Prohibition,' laughed Otis Guichet. 'They kept it in their pockets. We never closed.'"
Article on the unveiling of digitized database in 2012: http://www.nola.com/homegarden/index.ssf/2012/03/online_tool_allows_research_of.html