Although it was never completed, the site at Ollantaytambo gives archeaologists an insight into the construction techniques of the Incas. There are many stones on their sides, and there is a ramp that was used to drag the stones from the quarry on the other side of the valley, 6km away. Between the quarry and the site there are approximately 50 stones that were in the process of being brought to Ollantaytambo. What is particularly impressive is that these huge stones would have had to cross the river. How this was done is unclear, although there are suggestions that the Incas diverted the course of the water around the stones. Upon completion of the site, the ramp from the quarry would have been destroyed.