The Niger River begins near the coast of Senegal and Guinea and flows east into the Sahara desert, where in Mali it spreads out to form a huge delta, far inland from the sea. In this landscape of flat, annually flooded land stretching from horizon to horizon, various kinds of native rice have been cultivated for thousands of years. Big river boats go from Mopti, the main river town, down to Timbuktu for salt and up to Bamako for timber, a total distance of 500 miles.