This 100 mile detour begins and ends on I-10 near Palm Springs, and may just be the highlight of your trip across southern California. The route heads south from Banning, CA and loops back north thru Palm Springs. Other areas of interest nearby are Joshua Tree National Park and the Salton Sea.
Joshua Tree National Park
Night Sky Festival: October 28-30, 2016
Salton Sea History Museum & Visitor Center
"Originally opened in 1959 as the North Shore Beach & Yacht Club, the newly renovated building is now a historic site. The Albert Frey designed building was re-opened on May 1, 2010 and is home to the Salton Sea History Museum & Visitor Center." http://saltonseamuseum.org/salton_sea_history.html