The last time that I was on the Zócalo, about a week ago, there was a photographic exhibit with historic pictures showing the plaza as it use to be.
This undated photograph is a view of Zócalo looking north from the balcony of the city hall toward the Cathedral.
This picture, also undated, looks to the east toward the National Palace.
The Zócalo in 1938
Looking toward the Zócalo from 20 de Noviembre Avenue.
The buildings are illuminated for Independence Day in 1944.
The National Palace illuminated for Independence Day in 1944
The Zócalo in 1954