The Pongo de Manseriche is a river gorge in northwest Peru. The Marañón River runs through this gorge before it reaches the Lower Amazon Basin. The Pongo de Manseriche is 3 miles (4.8 km) long, located at 4° 27' 30" South and 77° 34' 51" W, just below the mouth of the Rio Santiago, and between it and the old missionary station of Borja. According to Captain Carbajal, who descended the Pongo in the little steamer Napo, in 1868, it is a vast dent in the Andes about 2000 ft (600 m) deep, narrowing in places to a width of only 100 ft (30 m). Through this dark canyon the Marañón leaps along, at times, at the rate of 12 miles per hour (19.3 km/h, or 5.36 m/s). The Pongo de Manseriche was first discovered by the Adelantado Juan de Salinas. He fitted out an expedition at Loja in Ecuador, descended the Rio Santiago to the Marañón, passed through the Pongo in 1557 and invaded the country of the Maynas Indians. The pongo is a frightful series of torrents and whirlpools interspersed with rocks. There is an ancient tradition of the indigenous people of the vicinity that one of their gods descended the Marañón and another ascended the Amazon to communicate with him. They opened the pass called the Pongo de Manseriche (Wikipedia).