The nomadic herdsmen of the Bakhtiari ethnic group move their livestock and families to grasslands in Iran. The people and their animals cross the mighty Karun River by making rafts held afloat by inflated goat skins. Animals are strapped to the rafts and cross the river. Men and boys swim as do most of the larger animals. They are swept long distances along the river and clamber out over rocks, only to be faced with mountains to cross.
(NOTE: Known as Grass, this film was made by Merian C. Cooper, Ernest Schoedsack, and Marguerite Harrison. Here's another clip.)