James Arness did some PSA's in the late 60s or early 70s which I recently had the pleasure to see on a film reel. These, along with active campaigning by he and his brother helped prevent development in Rustic/Santa Monica Canyon and the beaches they open to. The area has been free of big developments with only one corporate logo at the canyon's entrance (gas station, which has been there forever - as with most of the canyons going up PCH), and it is now among the most valuable residential areas in California. This would not have been the case without his (now) little known contribution.