Cusco and Machu Picchu, Peru.
Despite the latter being the poster image (top photo) of the Inca Empire, they ruled from Saksaywaman (near Cusco) eighty kilometers away. In my mind the massive walls of Saksaywaman (lower image) are more striking than the re-constructed temples, homes and terraces of Machu Picchu. (The photograph does not reveal that the far hills are separated from Machu Picchu by a river gorge, which effectively creates a thousand-foot-deep moat on three sides of the site.)
Particularly remarkable is the similarity of Saksaywaman’s finely-fitted massive walls to similar constructions, such as the cyclopean walls of Mycenae half a world and several millennia away, and Osaka Castle, closer in time but more remote culturally.
Machu Picchu’s site and modern reconstruction renders it more photogenic, despite its being a subsidiary outpost of the Inca. After the Spanish conquest, the site of Machu Picchu site was covered by jungle and known only by locals until the twentieth century. If you have the opportunity, visit both as we did.
The particularly fit can trek from Cusco to Machu Picchu along paved trails of the Inca. The distance challenges less than the altitude, which starts at 12,000 and descends to 8,000. We didn’t make that trek but did in 2003 climb Huayna Picchu, the hill overlooking Machu Picchu, to a tiny (perhaps priestly) community site for a selfie (since lost).