Tambo Colorado
The great Inca Pachacutec himself probably stayed at this, one of Peru's most underrated archaeological sites. The labyrinthine alleyways and trapezoidal plaza of this huge adobe settlement were devised as an outpost for soldiers and visiting dignitaries of the far-flung Andean empire, making it the most important Inca site on the Peruvian coast. Today, Tambo Colorado is incredibly well preserved, owing to its bone-dry setting. When you go, you'll feel some of the same grandeur found in the stones of the Sacred Valley around Cuzco.
Tambo Colorado, or Pucahuasi ("red resting place") in Quechua, derives its name from the bright bands of imperial red, yellow, and white with which it was once blazoned. The site comprises several sections laid out around a large central plaza, and you can see the quarters where the great Inca received his guests. Notice that the plaza's distinctive trapezoid shape is mirrored in many of the tambo's architectural features, such as the trapezoidal windows and portals. Modern engineers have argued these elements are anti-seismic in nature, something that is highly necessary in this volatile region.
Be sure to visit the on-site museum, which houses many finds by the great Peruvian archaeologist Julio C. Tello, the site's excavator.