The fortress of Ollantaytambo is a towering complex of agricultural terraces, ceremonial plazas, and temple ruins that rises in dramatic steps from the main plaza up to a ridge with views across the entire Sacred Valley. The scale is immediately impressive — the terraces alone stand ten to fifteen metres high at their faces, built of precisely fitted stones without mortar in the Inca manner. At the summit, the unfinished Temple of the Sun displays six massive monoliths of pink rhyolite, each weighing more than 50 tonnes, that were being assembled into a wall when the Spanish conquest halted construction permanently.
The site requires some physical effort — the stairways are steep and the altitude is around 2,800 metres — but the views from the top justify the climb. You can see the Urubamba River winding through the valley, the town's grid of Inca streets laid out below, and the Pinkuylluna storehouses on the opposite hillside. The site includes a ceremonial bath complex called the Water Temple at the base of the terraces, where a carved stone fountain still runs when the water table is high.