Cumbe Mayo (3600 m), a pampa on a mountain range, is 20 km southwest of Cajamarca. It is famous for its extraordinary, well-engineered pre-Inca channels, running for 9 km across the mountain tops. It is said to be the oldest man-made construction in South America. The sheer scale of the scene is impressive and the huge rock formations of the trail to the site starts from the hill of Santa Apolonia (Silla del Inca), and goes to Cumbe Mayo, straight through the village and up the hill. At the top of the mountain, leave the trail and take the road to the right to the canal. The walk is not difficult and you do not need hiking boots. Take a good torch/flashlight. The locals use the trail to bring their goods to market.