Query: When did Mexico City lost most of its artifacts? 
Context: Since the mesoamerican pre-Classical period the inhabitants of the settlements around Lake Texcoco produced many works of art and complex craftsmanship, some of which are today displayed at the world-renowned National Museum of Anthropology and the Templo Mayor museum. While many pieces of pottery and stone-engraving have survived, the great majority of the Amerindian iconography was destroyed during the Conquest of Mexico.