Amazonian oven. Replica of a cassava oven used by the indigenous people living in the Amazon Basin region. Cassava, also known as manioc or yuca, is a plant that is a staple of the traditional Amazonian diet, and the third largest carbohydrate source for humans in the world. Only the starchy tuberous root is eaten. Cassava root is highly toxic when raw, as it contains the poison cyanide, so it needs to be carefully prepared in order to be eaten safely. One procedure is to grind it into a fine powder and then soak it in water to wash out the poison. The excess water is then squeezed out before cooking. Here, the root is placed on a flat plate (upper centre) and toasted over the fire.