the -- actually pre first world war and they're amazing and held by pacific ariel survey off,,hagen burger road by the airport. what they did in the early era is they had a large format cameras that they went with the originals over the city and did long exposure photos with very high resolution lenses so when you want to find something in the archives, they'll give you aqua drant go to and a loop and you can't see much resolution but they will blow it up for you and the resolution will be so high you will be able to determine the make of many of the autos you see on the street. in the teens and 20s. >> so let's go back to learning history of your building to find out when was your buildingibility and who built it. what do you think moses? >> for the newer buildings i believe their data base comes from building permit records. >> how do people access that. >> sfgov dot org. you're going to tell he is a historicle person. for newer buildings after the 06 earthquake. you mean the 89? >> one of the greatest faults with the assessors data base is they make up date for builds that pre existing