The document discusses several colonial cities in Mexico that are known for their historic architecture and cathedrals, including Puebla, Morelia, Guanajuato, San Miguel de Allende, Zacatecas, Querétaro, Guadalajara, and Mexico City. It provides some brief details about the cathedrals and historic aspects of each city, noting that Puebla and Morelia have some of the tallest cathedral towers, while Guanajuato is known for its museum of mummies. Mexico City is described as one of the largest cities in the world with some of the country's most famous colonial architecture and cathedral.