Maasai warrior in front of Lake Natron in northern Tanzania, one of the most alkaline lakes of the Rift system. As its waters evaporate in the intense heat, sodium sesquicarbonate, known as trona or natron, solidifies to resemble giant coral heads in brightly coloured water.The pastoral Maasai graze their cattle along its southern shores where the Enkare Sero River provides welcome pasture.