the architecture in the historic center is characterized by the prominence of ashlar, the use of which begins in the last third of the 16th-century. this volcanic stone, white or pink exceptionally soft, lightweight, and weatherproof, emerged as a seismic structural solution. the ashlar was unable to take the early years, except for the covers of the main church and some houses. the original city was built with adobe, masonry, sticks and straw roofs or mud pie. houses of this type were made until the nineteenth century and were common in the eighteenth century, some remain in the original district of san lazaro. later came the brick and tile houses with tile found in the monastery of santa catalina. the cataclysm of 1582 settled these systems and raised the earthquake reconstruction. then came the ashlar as prime structural solution.