The Festival of the Sun is the Inca Empire's most important ceremony, revived in Cusco in 1944 after four centuries of suppression. Thousands of performers in authentic Inca costume recreate the ancient ritual at three sites across Cusco, culminating at the fortress of Sacsayhuamán above the city. The Inca Emperor is carried on a golden litter to pay homage to Inti, the sun god. Against the backdrop of Andean mountains and Inca stonework, it's one of the most visually striking cultural events on earth. June 24 is also Peru's Day of the Peasant — the whole country celebrates.
The main ceremony at Sacsayhuamán starts around 1pm and lasts several hours. Arrive early for standing room near the stage. June is Cusco's dry season — perfect weather. Acclimatize to altitude for 2–3 days before arrival.