Ucayali River
Fitzcarrald discovered a short passage overland between the Mishagua River, a tributary of the Urubamba, and the Manu, a tributary of the Madre de Dios River. The former leads into the Ucayali River. The Isthmus of Fitzcarrald was later named for him, as discovery of this route enabled transport of rubber from the Madre de Dios region. It was transferred to ships on the Mishagua, which could reach the Urubamba, the Ucayali River and thereby down the Amazon to markets and Atlantic ports for export.