The Bronson Caves in Griffith Park Los Angeles used to be where they filmed some of the Batman TV series with Adam West. The Caves are closed due to erosion coming from the entrance now. The caves are also close to the Hollywood Sign and you can see the sign from a distance. Hike a bit further and you can see the sign close up.
Medium: 9 x 12 in oil on canvas sheet
original painting can be bought here: https://21fd5d-ab.myshopify.com/products/griffith-park-bronson-caves