Don’t forget to bring your passport with you to Machu Picchu (it’s required). At the entrance of the Incan ruins, you can add a special Machu Picchu stamp in your passport!
Having a free day in Cusco is a great way to adjust to the altitude and explore the Inca heritage of the city.
There are other breathtaking destinations, not only Machu Picchu. If you have extra time, explore other areas of Peru - visit the mountain destinations of Huaraz or Cajamarca, go sand duning in the desert of Ica and Paracas, or spend time in the Amazon Rainforest.