^ Ok, but had you heard of it before seeing it in this thread? I had not.
There are probably way better examples of hidden gems around Southern California, but the first thing that popped into my head is the large public art installation by famed artist Isamu Noguchi called "California Scenario". It's in Costa Mesa (Orange County) behind a totally nondescript 80s office building, and across a giant road from the huge South Coast Plaza mall. I only found it because I had heard of it and knew where to look. You walk along a little sidewalk next to the building, and suddenly this beautiful installation appears. It's really surreal.
And here's the setting, including the building the piece sits behind:
street view:
https://www.google.com/maps/@33.6884...4!8i8192?hl=en
aerial:
https://www.google.com/maps/place/No....8822393?hl=en