Above the fortified terracing in Ollantaytambo, there lies a mysterious building romantically known as the “Temple of the Sun”. These stones are unique, their straight sides and unusual spacers being in total contrast to the multi-faced joints and beveled edges of other megalithic walls in Peru.
Exactly how the stones were so perfectly shaped is unknown, since they were carved out of red porphyry, a stone as hard as granite. The great mystery of Ollantaytambo is how these six 50-ton stones were moved to their present location, since the quarry from which they came has been definitively identified at Chachicata four miles away across the valley on the opposite mountainside! Having first quarried the stones, it would be necessary to take them down a steep mountain slope, across a river, and then up another steep mountain slope to the construction site. 
Spanish historian Garcilaso de la Vega tells of a disaster that occurred while the Incas were transporting a large stone from a quarry to Ollantaytambo. The stone is known as ‘sayccusca rumi’ (‘tired stone’) and measures 6.2m long, 4.6m broad, and 1.1m thick. It was brought across the river but abandoned 780 yards from the ascent to the ruins. 
He writes: “The historical truth, as related by the Ynca Amautas, who were the wise philosophers and doctors in the time of their idolatry, is that more than twenty thousand Indians dragged the stone with stout cables. They proceeded with great difficulty, as the road was very rough, and passed up and down many steep mountains. Half the people hauled upon the cables in front, while the other half held on behind … In one of these steep places the weight of the stone overcame the force of those who held it, and it slipped down the hill, killing three or four thousand Indians who were guiding it.“