Sanxingdui (c. 1700–1100 BC) represents a sophisticated Bronze Age civilization in the Sichuan Basin with a distinctive artistic tradition. The large eyes on bronze masks likely represent a cultural ideal or mythological being specific to the Shu culture, not aliens. The site's unusual nature reflects regional isolation — the Sichuan Basin was geographically separated from Yellow River civilizations. Recent excavations (2020–2022) have found new pits with thousands of additional artifacts, advancing scholarly understanding.