7.7853°S, 78.0783°W.
Marcahuamachuco is a monumental highland complex in the Sanchez Carrion province of La Libertad, northern Peru, perched on a ridge at 3,650 metres elevation. Occupation dates from roughly 350 to 1000 CE, with the principal monumental construction belonging to the Huamachuco culture and largely predating Wari expansion into the region. The site covers 240 hectares and is dominated by massive multi-story circular and rectangular gallery structures, some preserved up to 12 metres in height — among the tallest pre-Inca standing architecture in the central Andes. Construction is in coursed flat slabs of local sandstone laid without mortar. John Topic and Theresa Topic conducted systematic mapping and excavation beginning in the 1980s, identifying the Castillo, El Convento, and Cerro Viejo sectors. The galleried compounds enclosed central courts and likely served ceremonial and ancestor-veneration functions.
The slab walls still rise unbroken along the ridge crest, visible from the modern town of Huamachuco kilometres away.