In 1978 a city worker's shovel hit an Aztec monolith, the Coyolxauhqui Disk. The great temple of Tenochtitlán had resurfaced! Levelled by the Spanish to build their own sanctuaries, its remains now lie at ground level; but thanks to its successive reconstructions over time (7 nested pyramids), two twin temples can still be seen, one of which has a sacrificial stone at its summit. The Eagle Warriors wall and its bas-reliefs have also been well preserved.