Monumento Arqueológico de Wilcahuaín (7 km north of Huaraz, 8 a.m.–5 p.m. daily, US$2) consists of two imposing stone buildings constructed around A.D. 600–900, when the Huari empire expanded north from the Ayacucho [1] area and took over the local Recuay civilization.
The main building has a gravity-defying roof of thick stone slabs and three floors of finely wrought, spooky stone chambers. These rooms once held the mummified bodies of prominent leaders, kept dry by ventilation ducts running throughout the complex. The outer walls were decorated with sculpted heads, one of which remains today in the shape of a mountain lion.
Wilcahuaín stands out from other ruins in Peru because it is an intact building that requires no imagination to understand. Bring your flashlight in case the electricity goes out, as it did when we were there. Combis marked Wilcahuaín cost US$0.60; ask your hotel for directions to the bus stop. Or take a cab (US$2). The two ruins are a few hundred meters apart along a dirt road. This makes for a pleasant two-hour walk back to town through countryside and villages.
Links:
[1] http://www.moon.com/destinations/peru/central-highlands/ayacucho