The Donner Summit Weather station guided planes across the summit and across he country on the first transcontinental air route. On the roof of the weather station pilots could see "SF - SL" and "15". Salt Lake City was in one direction and San Francisco in the other. The station was 15 so pilots would then fly to 14 or 16. The station also provided weather information. Today only the foundation exists and iron embedded in the grantie that held cables strung over the station to keep the winds from blowing it away. The view is great.