“It came as quite a surprise to local history buffs, that in 1930 the famous Mexican artist and muralist Diego Rivera came to Grass Valley and Nevada City,” according to Elinor Barnes, writing for the Nevada County Historical Landmarks Commission.
“He and his also famous wife, Frida Kahlo, were staying in San Francisco. Rivera was working on the completion of two murals – one at the San Francisco Stock Exchange Tower, and the second at the San Francisco Art Institute. “Rivera was interested in obtaining real-life sketches of miners and the mining industry to use on his murals. The Morning Union newspaper noted his coming on Dec 7, 1930, and followed this mention with another article on Dec 10, 1930.
“It mentioned Rivera’s interest in painting the three great industries in California – mining, agriculture, and horticulture. Recent information about this little-known visit notes that he completed fifty-one sketches, which included forty-nine in charcoal and two landscapes in watercolor. Many of these works were completed while visiting the Empire Mine.
“Before Rivera left California, he gave his sketches to a friend for safekeeping, and these remained unknown to the public for sixty years. In 1997 the Getty Research Institute purchased the sketchbook and it was then described in recent journal papers.
“Such an unusual discovery has prompted a great deal of local historical interest. The Nevada County Historical Landmarks Commission, as one such group, has taken on the project and will, in the future, make available more detailed information about this exciting event.” — Elinor Barnes
Jeff Pelline's Sierra Foothills Report 
Interesting bit of history. Thanks Jeff!
Yes it is. Thanks. BTW, the “creatures of the night” are back on this blog, seeking to post irrelevanat comments at 2:45 a.m. Get some rest!
Or maybe they can give it a rest?
That is interesting. I wonder if they would be impressed to know that I visited their quarters when I was in Mexico City. 🙂