Puno City

Puno needs 2 days: the city on one, and a boat trip on Lake Titicaca (the world's highest navigable lake, at 3,812m) on the other. April-October is the dry season, though nights are cold year-round due to the altitude. It's inexpensive compared to Cusco, though the extreme altitude calls for an extra acclimatization day before any excursion. Its Lake Titicaca is home to the Uros Floating Islands, built entirely from totora reeds, where indigenous communities still live traditionally on the water.