The Inca Bridge (Puente del Inca) isn't a construction of the Incas, but a natural arch that forms a bridge over the Vacas River, a tributary of the Mendoza River. Puente del Inca is also the name of the nearby hot springs. Scientists speculate that interaction between ice and hot springs was involved in the origin of the formation. They suppose that in ancient times ice covered the river and acted as support for avalanches of snow, dust and rocks. So the dust over the ice over the river would have served as a path for the sulfurous water and petrified the surface, so when the snow melted, the bridge (48m long, 28m wide and 8m high) remained by itself.
