Visit the Sacred Valley [1], Cusco [2], and Machu Picchu [3].
Visit all of the above but extend your time in the Sacred Valley to hike, mountain bike, and go horseback riding. Add on a hike along the Inca Trail [4] or the Salcantay trek to Machu Picchu [5], or experience the Amazon [6] around Puerto Maldonado [7] or the Manu Biosphere Reserve [8].
Add an overland adventure from the Moche, Sicán, and Sipán archaeological monuments of Peru’s northern coast up into the Chachapoya cloud forest. This remote corner of Peru is rich in exotic birds, lost cities such as Kuélap, and off-the-beaten-path treks.
Links:
[1] http://www.moon.com/destinations/peru/the-sacred-valley
[2] http://www.moon.com/destinations/peru/cusco
[3] http://www.moon.com/destinations/peru/machu-picchu
[4] http://www.moon.com/destinations/peru/machu-picchu/machu-picchu-hikes-and-treks/inca-trail
[5] http://www.moon.com/destinations/peru/machu-picchu/machu-picchu-hikes-and-treks/salcantay-trek-machu-picchu
[6] http://www.moon.com/destinations/peru/the-amazon
[7] http://www.moon.com/destinations/peru/the-amazon/puerto-maldonado
[8] http://www.moon.com/destinations/peru/the-amazon/manu-biosphere-reserve