Hiding in plain site above the city of Los Angeles are World War Two air raid sirens. Put up to warn of a incoming aerial attack, there are still 200 of them looming above the city. Once you notice one you cant unsee them. A complete map of the remaining air raid sirens: https://www.google.com/maps/d/viewer?mid=1ERKoD9Wb0FBOcJZou7uKnocmI-Q&hl=en_US&ll=34.05005297675974%2C-118.18817949999999&z=9 For more documentary vids covering Los Angeles history, culture, and urbanism follow Heart of the City: https://www.youtube.com/channel/UCioj1xWsiDNQwnk0_5eW4jA