The Magdalena River, the only living body of water in the city, rises among pine and oyamel forests. It is located in Los Dinamos National Park, named after the four generators installed in the nineteenth century to supply energy to the textile and paper mills that existed in the south of the capital. The place is ideal for a wide variety of outdoor sports; for example, in its more than 2,000 hectares (over 4,942.108 acres) there are 26 kilometers (16.16 miles) of trails for biking or hiking of all levels. The most demanding trails are found in the 3rd and 4th Dinamos, as well as the viewpoints of La Coconetla and Puerta del Cielo, while the 1st and 2nd Dinamos have more infrastructure and amenities for children and the elderly. In its walls and ravines you can also practice climbing, rappel and go up the Via Ferrata, a marine staircase embedded in rock. It is worth going there for an early morning walk listening to your footsteps, the murmur of the river and the birds singing.