The main quarry of Machu Picchu lies on the hillside just past the Main Gate [1]. However, there are two more quarries beside the Sacred Rock [2] and another below the Secular Area [3]. Some houses are found in the Main Gate quarry, and they probably belonged to the workers.
Returning to the main path, walk down the main stairway of the citadel, which has 16 different fountains that are all interconnected. The first fountain is on the right hand side before arriving at the rest hut.
From this first fountain, walk downhill following the water into the Royal Tomb and Temple of the Sun [4], the most sacred of Machu Picchu’s religious areas.
Links:
[1] http://www.moon.com/destinations/peru/machu-picchu/ruins-tour/main-gate
[2] http://www.moon.com/destinations/peru/machu-picchu/ruins-tour/sacred-rock
[3] http://www.moon.com/destinations/peru/machu-picchu/ruins-tour/secular-area
[4] http://www.moon.com/destinations/peru/machu-picchu/ruins-tour/royal-tomb-and-the-temple-the-sun