April 1, 1920: The Times reports on the increasing popularity of Easter sunrise services, an observance held on Mt. Rubidoux for the first time in 1909. 

“The unique feature of Easter in Southern California is the sunrise service. Since the first Easter sunrise service was held on Mt. Rubidoux, Riverside, the idea has been adopted throughout the this territory to such an extent that in probably every important town in Southern California some sort of sunrise service will be held. Great actors and noted singers will take part in some of these services, and in all the idea emphasized will be that the out-of-doors — the Earth, the sea, the mountains, the dimming stars and the rising sun — are visible proofs of an all-provident Creator whose powers are beyond human conception.”

March 24, 1913: A sunrise service on Mt. Rubidoux.