Unit 5, the amazing Amazon. The Amazon is an amazing river. It is unique in many ways. It is the second longest river in the world. It is 6,500 kilometers long. It starts up in the Andes Mountains. Its drainage basin, the area of land that collects water, covers 40% of South America. The Amazon River has many small rivers that supply it with water. It is the widest river in the world. The river rises more than nine meters during the rainy season. It overflows its banks. It floods large areas of the rainforest. During that time, in some parts, it has a width of up to 40 kilometers. The Amazon River is over 325 kilometers wide at its mouth. It has more water than any other river in the world. The Amazon River is also home to many animals. Over 2,000 types of fish live in the Amazon River. One kind of fish is the piranha. The piranha is a terrifying fish. A piranha grows up to 60 centimeters long. It hunts in a group. A group of piranha can kill and eat cattle in a matter of minutes. They are so efficient that only the bones are left. This fish is one of the most dangerous creatures in the Amazon River.