Mount Diablo is the highest mountain in the Bay Area and was the meridian point for all the surveying that was done in California's early days. Before that, it was a home to the Miwok people as well as a spiritual point for all the tribes of the region (who were brutally and sadly the victims of colonial genocide when they were forced off their land and subject to disease and privation such that most of them died).
We had a team-building weekend planned there, which meant basically a night of camping. It was beautiful weather, hot but not too hot. We did a long 3.5 hour hike in the afternoon on Saturday around the front and up the side and then I did a shorter hike on my own from the summit to the shorter north peak, where I lost my watch.
It's beautiful, desert-like hills with turkey vultures catching thermals and little gophers running around. Glad I had the opportunity to go.