The Place
Cusco sits at 3,399m. Fly there directly from sea-level Lima and altitude sickness is a real risk, even for a fit 45–50 crowd. The Sacred Valley floor sits roughly 500–600m lower — mild enough to let everyone's body adjust for two nights before going any higher. That's the practical reason it's Day 2, not an afterthought.
But it earns its three nights on its own merits. Pisac's Sunday market is still where locals from surrounding villages come to trade, not a tourist recreation of one, and the ruins above town step down the hillside in Inca terracing that's still in active agricultural use. Moray is stranger — concentric circular terraces cut into a natural depression, with a temperature difference of several degrees between the top and bottom ring. Nobody's fully settled on why the Incas built it that way; the leading theory is an agricultural testing ground for crops at different microclimates, all within a few hundred meters.
Maras is the valley's most photographed corner: thousands of small salt pools terraced into a hillside, fed by a natural spring, harvested by hand in a method that hasn't meaningfully changed since before the Inca Empire. It's also just a genuinely strange, beautiful landscape — glinting white and pink in the right afternoon light.