Reaching 2,046 metres in height, the Three Brothers comprise Eagle Peak (the uppermost ‘brother’) and Middle and Lower Brothers. In this photograph, the Merced River flows in the foreground. Born in New York state in 1829, Watkins went west during the California Gold Rush and became a pioneering photographer, renowned for his landscape shots of the western USA. He created outsize glass negatives known as mammoth plates in order to portray the scale and grandeur of his subjects, and produced ‘stereoviews’ for the stereograph, which gave his images an illusion of depth. Watkins’ photographs are credited in part with persuading US president Abraham Lincoln to protect the Yosemite Valley in law, paving the way for the establishment of the national parks system

Photograph from the archive of the Royal Geographical Society