<Table> Sun Stone <Tr> <Td_colspan="2"> Sun Stone, at National Anthropology Museum in Mexico City, Mexico </Td> </Tr> <Tr> <Th> Material </Th> <Td> Basalt </Td> </Tr> <Tr> <Th> Discovered </Th> <Td> 17 December 1790 at El Zócalo, Mexico City </Td> </Tr> <Tr> <Th> Present location </Th> <Td> National Anthropology Museum, Mexico City </Td> </Tr> </Table> <Tr> <Td_colspan="2"> Sun Stone, at National Anthropology Museum in Mexico City, Mexico </Td> </Tr> <Tr> <Th> Material </Th> <Td> Basalt </Td> </Tr> <Tr> <Th> Discovered </Th> <Td> 17 December 1790 at El Zócalo, Mexico City </Td> </Tr>

How many rings does the aztec calendar have