City workers in 1978 were surprised when they unearthed the Coyolxauhqui Stone. Was there no suspicion of ruins in Mexico City at all? How was it such a surprise!? Was the entire civilization forgotten until 1978? Was exact the location of the ancient city speculative before then? Was it assumed everything was just completely gone?

It seems to me that if you dig in a gold mine, it wouldn’t be a shock to find gold.