The landscape of the State is marked by mountains, valleys and caverns. In the Serra do Cipó, Sete Lagoas, Cordisburgo and Lagoa Santa, the caves and waterfalls. Minas Gerais is the source of some of the biggest rivers in Brazil, most notably the São Francisco, the Paraná and to a lesser extent, the Rio Doce. The state also holds many hydroelectric power plants, including Furnas dam. Some of the highest peaks in Brazil are in the mountain ranges in the southern part of the state, such as Serra da Mantiqueira and Serra do Cervo, that mark the border between Minas and its neighbors São Paulo and Rio de Janeiro. The most notable one is the Pico da Bandeira, the third highest mountain in Brazil at 2890 m, standing on the border with Espírito Santo state. The state also has huge reserves of iron and sizeable reserves of gold and gemstones, including emerald, topaz and aquamarine mines.