From Aztec times , the Centro Histórico used to be where the wealthy and elite lived . However , in the early 20th century , these classes began to move to areas west and southwest of the Centro , to neighbourhoods such as Colonia Juárez , Colonia Cuauhtémoc , Colonia Roma and Colonia Condesa . The Centro remained the commercial , political and intellectual center through the mid 20th century , although it was around this time that UNAM moved most of its facilities to the new Ciudad Universitaria . The reason for the decline of the city center was partly man-made and partly natural . In the 1940s , the city government froze rents so that until 1998 , when the government repealed the law , tenants were still paying what they were in the 1950s . With no financial incentive to keep up their properties , landlords let their buildings disintegrate . The 1985 earthquake took its toll on a number of these structures , which were never fixed or rebuilt , leading to slums with and garbage-strewn vacant lots . The result was the loss of about 100,000 residents of the " Colonia Centro " , leaving the area almost deserted at night
1985 earthquake
1985 Mexico City earthquake
History of Mexico City