The other half of Ollantaytambo, Araqama Ayllu, is across the Río Patacancha. The main square is fronted with a series of monumental buildings, and above is the temple that was being constructed when the Spaniards arrived—and was later converted into a fortress by Manco Inca.

Two hundred steps lead up terraces to a double-jamb gateway and the Temple of Ten Niches, a long wall with odd protuberances. Some say these bumps draw heat away from the slabs, preventing them from expanding. Others say they somehow served in the transport of the blocks. Or perhaps the Inca valued them as we do today, for the graceful shadows they cast across the stone.

Above is the unfinished Temple of the Sun, considered one of the masterpieces of Inca stonework. Six giant monoliths of pink rhyolite are perfectly slotted together with thin slices of stone and oriented to glow with the rising sun. Traces of the chacana symbols and pumas that once decorated the walls can still be seen.

What is unusual about the wall is the long straight lines—and the molten bronze that was poured in the T-joints to hold the wall together. These features indicate the wall was probably the handiwork of Lake Titicaca’s Colla Indians, who were brought to work here by Pachacútec as part of the forced labor system known as mitimayo.

According to J. P. Protzen, the wall was probably intended to be one side of a great platform, which seems likely with the unfinished blocks, rough walls, and plaza nearby. It is uncertain why the construction stopped—perhaps it was Pachacútec’s death, a rebellion of the Colla Indians, the smallpox epidemic of 1527, or the arrival of the Spaniards.

To the left of the plaza, the Cachicata quarry appears high on the hillside. The Inca dragged boulders weighing up to 52 tons down the mountain, across the Río Urubamba and the valley floor, and then up a steep ramp—the top of which is at a 25-degree angle, three times that allowed on most U.S. highways! Ollantaytambo expert Vincent Lee used sleds and levers to show how the Inca moved such blocks up the ramp, which still leads up the hillside to the temple. On the ridge above the temple are rougher buildings and the Incahuatana, the hitching place of the Inca, where prisoners may have been lashed into the human-sized portals.

At the base of the ruins are the Princess Baths, a half dozen fountains adorned with chacana symbols. Some of the fountains are engineered in such a way as to cause a whirlpool that allows sediment to drop before the water continues over a delicately shaped spout. On the steep flanks of Pinculluna, the sacred hill that rises above the Inca town, are the ruins of several granaries, which glow in the afternoon sun.