Fantastic Map Dates Every Last Building in Los Angeles

Finding out a building's age used to require at least a little legwork, but now there's a simple and great-looking way to see how old pretty much any structure in the county is. This interactive map, built: LA (via CityLab), uses information from the Los Angeles County Assessor's office and the LA County GIS Data Portal and shows every building in LA County, color coded by age; hovering over a structure on the map reveals the specific year it was built. (No more lying about your age, buildings.) Zoom out to look at the entire area and see where the buildings are predominantly bright blue/older (Mid-City, Exposition Park) or mostly purples, signifying that they were built in the 1950s, '60s, and '70s (big chunks of the Valley, like Granada Hills and Van Nuys).

It's not exactly news that the Valley had a post-WWII boom or that Mid-City has old buildings, but what makes this map addictively explorable—aside from the impressive fact that the whole county is on it—is being able to see all the buildings fitted together, getting a look at where the old and new mingle and where they exist almost exclusively. Don't miss clicking the stopwatch icon, which starts at the pre-1909 buildings and slowly adds decade after decade until every structure is represented. It's like watching the city be built in just a few seconds.

· Built: LA [Official site]
· Watch the Strange Growth of Los Angeles, From 1877 to 2000 [Curbed LA]