Cusco for example lies on a radial plan, mimicking the sky and pointing to specific astronomical events on the horizon.
Similarly to the ancient Egyptians, this was a horizon-based culture. They built carefully placed pillars on mountains and hills overlooking Cusco, so when the sun rose or set between these pillars, they knew they had to plant at a specific altitude.
The Incas are known to have built observatories in many different places where they captured the first and last rays of the Sun through a series of specially placed windows.
Their chief observatory was called the Coricancha (Qurikancha) or ‘golden enclosure’, and was completely covered in gold (inside and outside), revealing their dedication to the Sun God.