Introduction to the Puerta del Sol: The world-famous Puerta del Sol is a door made of a huge stone block, with a human-shaped bas-relief surrounded by the sun's rays. Next to the "Gate of the Sun" is a rectangular platform made of stone, 118 meters long and 112 meters wide, which is called "Calasasaya" in the Indian Quechua language. According to archaeologists' analysis, it may be an altar used by the ancient Inca Empire to worship the sun god.