Machu Picchu's secret sister — just as imposing, but without the crowds. To reach Choquequirao you walk four days, dropping into and climbing out of the canyons of the Apurímac River: no train, no cable car, no shortcut. The reward is Inca terraces and temples wrapped in cloud forest, of which barely 30% has been excavated. Whoever makes it, makes it on their own merit. And almost always, makes it alone.