When you stand in the main plaza of Cusco you stand in the middle of history. The site of the birth of the Inca, the site of the death of the Inca, the site of conquistadors success, the site of architecture, and artisan markets, and restaurants, and hotels. In 2016, Cusco is a melting pot.
The middle of the plaza features the statue of an Inca Emperor, surrounded by a beautiful waterfall. Benches are provided so you can catch your breath; you are at 11,200 feet altitude, you know.
Two sides of the plaza feature Spanish cathedrals, both of which you can tour or attend mass. High above the plaza you can see Cusco's version of the Cristo Blanco statue. You can also see the tail end of the Saqsayhuaman fortress ruins of ancient Inca.
At night, the lights creep up the mountainside to create an unforgettable view. During the day you could see a llama, or a parade, or just a local artist trying to make a living.
You can go for a walk in any direction and see something incredible. Or, you can sit right there, mid-plaza, and take in Cusco in all of it's wonder.