I was certain this gathering of turrets was another creation by Leo until I ran into Leo himself. "Not this time," he said. So I don't know who made the little castles in the foreground.
The fortress in the background is the Devil's Gate Dam. I know who built that, if Wikipedia's article is correct (though I think Wikipedia's a place to begin one's research rather than end it): the Los Angeles County Flood Control District built the dam in 1920.
Hard to believe we ever needed flood control, isn't it?
All things change. Even castles are impermanent. Droughts too, and that's no fairy tale.