Stock Photo - Larga and Negra Lagoons in the Sierra de Neila. Burgos. The Larga and Negra Lagoons are located in the Sierra de Neila, in the province of Burgos. These lagoons are one of the main tourist attractions of the mountains and are located at an altitude of 1,514 meters above sea level. Both lagoons are fed by the waters of the rivers that are born in the Sierra de Neila. They are surrounded by an alpine landscape made up of meadows, forests and high-altitude mountains. Laguna Larga is located in a wide valley surrounded by several snow-capped mountains. The Laguna Negra, for its part, is located in an area close to the Laguna Larga and surrounded by a number of trees.