The first photo on this page was taken at a historic site of
Cusco. The second and the third ones were taken in Taquile
Island, which is located in Lake Titicaca, the highest navigable
lake in the world (3811 M, 12,500 ft.). The island has many
pre-Inca and Inca ruins and terraces, but hiking around the
island is extremely challenging due to the high altitude. I took
preventive medicine 48 hours before arriving at the island and
therefore I didn't experience any high altitude syndromes.