THE SACRED RIVER OF THE ANDES.

Water is the source of life, energy and absolution to many communities around the Andean mountains.
The natural history of the Inca Sacred Valley is a tale of mighty glacial rivers carving through solid earth to shape one of the most environmentally diverse basin in the Peruvian highlands.
Cutting through the steep walls of the fertile Sacred Valley, 20 km to the North of Cuzco, surrounded by foothills and snowy peaks that climb higher and higher, the Uru'Bamba River, known in Quechua as Willcamayu, was, for the Incas, a direct reflection of the celestial river known to them as "Mayu" (Milky Way). Its flow was thought to mimic the shape of Mayu.
The Uru'Bamba Sacred Valley stretches around 100 km East to West along the Sacred Uru'Bamba River, from Pisac to Maccu Picchu, and is fed by tributaries cascading down the surrounded valleys and gorges.
The Milky Way, our own galaxy containing the solar system, is a barred spiral galaxy with roughly 400 billion stars. The stars, along with gas and dust, appear like a band of light in the sky from Earth. The galaxy stretches between 100,000 to 120,000 light-years in diameter.
For the Incas, whose empire was the largest in the Americas, the Milky way (Mayu) was a life-giver River in the heavens with its earthly counterpart -the sacred Uru'Bamba River, in the Sacred Valley. The Incas took control of the highlands region and the Sacred Valley along the Uru'Bamba River that was favored for its low elevations compared to other nearby areas, and warmer temperatures. Then they chose the Valley as their religious center and an agrarian laboratory. The growth of the unique corn that was used to make their fermented chicha for their religious festivals and ceremonial feasts, nestled there on the steep sides of the Valley's hills, and extensive irrigation systems were built transforming the region into an agricultural breadbasket. Besides the sacred corn, potatoes, quinoa, amaranth, etc. grew in the fields using the methods that the Inca developed through the knowledge of Mayu, and the dual forces of the universe acting in it that were reflected in the River's flow.
The Incas grouped the constellations into 2 different types: -luminous made up of sparkling stars that depicted geometric forms in the sky and were seen as inanimate, and -dark cloudy ones, contained within the dark blotches of the Milky Way, were seen as living forms, representing the silhouettes of animals that came to drink from the waters of the celestial River, obscuring the heavenly glow of Mayu.
In our present days, the sacred reflection of the heavenly River on earth, passes important ruins like Machu Picchu and the Raqch'i (Vira'Cocha) temple. The Incas observed  that the earthly manifestation of the sacred river was a collection point of the sacred water, that would then feed into the sky.
Today, the mountains with its crispy and thin air and the massive sky tumbling into the exceptional landscapes, Quechua-speaking farmers still work in the sacred fields  with methods unchanged since the ancient Inca era. But while the Sacred Valley is still deeply rooted in its history, the landscape is now a blend of the ancient and the modern world.
The Urubamba River is now best known for its great rafting and kayaking options. In some places, the sacred river passes marvelous stretches of jungle and thrilling rapids. As such, it offers travelers an exciting way to experience the outdoors from within the Sacred Valley. The river flow is at its fullest  between December and May -this is also when the rapids are best. When the water level drops from June through November, rafting is typically done along the lower section of the river between Ollanta-y-Tambo and Chilca.
The Uru'Bamba River originates on the slopes of the Cunu'Rana in the Puno Region, Melgar Province, near La Raya mountain range pass. The length of the River is 724 km. The Cunu'Rana (name comes from potatoes that belongs to the Quini group) is about 5,420m/17,782ft high, and lies South East of La Raya mountain pass near the road and railway that connects Cuzco and Juliaca.
The altitude at La Raya mountain pass, which makes the border between the regions of Cuzco and Puno, the Quechua and the Aymara speaking communities , is 4,335 meters
The Pongo of Mainique, a water gap 45m/50yd wide and 3km/2mi long, with 900m (3,000ft) to 300m(1,00ft)high cliffs, is the only break in the entire Vilcabamba mountain range that divides the Urubamba River between Upper and Lower Urubamba. The pongo is considered the most dangerous and turbulent whitewater pass on the Urubamba, however many boats traverse it, depending on seasonal river conditions. It is crossed by the Inca bridge, ancient secret entrance to Machu Picchu. The pongo is also a global biodiversity hotspot; 6 sq mi of rain-forest around the canyon contains more species of life than any other similar-sized area on Earth.