 Viewed from Machu Picchu's main sundial, the Southern Cross is above Salkantay's summit when at its highest point in the sky during the rainy season.The Incas associated this alignment with concepts of rain and fertility, and considered Salkantay to be one of the principal deities controlling weather and fertility in the region west of Cuzco.Salcantay is a large, steep peak with great vertical relief, particularly above the low valleys to the north, which are tributaries of the Amazon River.