Everyone has heard that the Incas were good engineers, but for a real look at just how good they were at land and water management, head to Tipón. Twenty kilometers or so south of Cusco, Tipón is a series of terraces, hidden from the valley below, crisscrossed by stone aqueducts and carved irrigation channels that edge up a narrow pass in the mountains. A spring fed the site and continually replenished a 900-cubic-meter reservoir that supplied water to crops growing on the terraces. So superb was the technology that several of the terraces are still in use today, and still supplied by the same watering system developed centuries ago. The ruins of a stone temple of undetermined function guard the system, and higher up the mountain are terraces yet to be completely excavated. Unfortunately, the rough dirt track that leads to the complex is in wretched condition. If you visit, either walk up (about two hours each way) or go in a four-wheel-drive vehicle (about 45 minutes to the site and 30 minutes back).
Visit the Travel Talk forums for help on planning your trip