In the early 16th century, there were over 400 huacas (shrines) in the Cusco Valley. Most were destroyed by the Spaniards, but the ones that remain are primarily the huacas carved into rock. Many huacas were oriented toward the June solstice sunrise, while others aligned with the Sun during the December solstice. Light tubes or cave openings were designed to illuminate altars at specific times, while other orientations guided the eye to the horizon on significant solar dates.

Pillars were strategically placed on hills to mark the Sun's passage across the horizon, serving as a calendar. The Incas meticulously studied the cycles of solstices and equinoxes, using this knowledge as a cornerstone of their annual crop management activities. In practical terms, this expertise was applied through horizon astronomy: the Incas tracked sunrises and sunsets on the horizon to measure time for agriculture and religious ceremonies.

Ultimately, these celestial orientations were integrated into their temples, huacas, and other structures, including solar pillars built specifically for astronomical purposes.