<Tr> <Th_colspan="2"> UNESCO World Heritage Site </Th> </Tr> <Tr> <Th> Part of </Th> <Td> Memphis and its Necropolis--the Pyramid Fields from Giza to Dahshur </Td> </Tr> <Tr> <Th> Criteria </Th> <Td> Cultural: i, iii, vi </Td> </Tr> <Tr> <Th> Reference </Th> <Td> 86 - 002 </Td> </Tr>

When was the great pyramid of giza excavated