in the monastery. In the colonial era, it was described as being as luxurious as the church of San Juan de los Reyes in Toledo and one of the most beautiful in Mexico. Since then, the complex has survived a number of earthquakes with little damage. In the 1990s, it became one of fourteen monasteries around the Popocatepetl volcano declared a World Heritage Site. The state of Puebla promotes tourism of the monastery through its "Franciscan Route," which connects it with other 16th-century Franciscan monasteries in Calpan and Cholula. The basic elements of the complex are the atrium with its corner chapels called "capillas posas," cloister, and main church. It is all constructed on a rectangular platform that measures 14,400m2 and rises six meters above the adjacent land. The complex is isolated from the outside by a thick stone atrium wall topped by merlons. These merlons are repeated on the walls of the church and cloister. These merlons are not the typical European style. Their form is similar to elements found in various pre-Hispanic constructions. The thick walls, merlons and narrow windows made the complex a fortress, not only to protect the monks from hostile native populations initially, but also to provide the local community later with a shelter in case of attack. The atrium of the monastery faces west, towards the main plaza of the modern city. Between this plaza and the main access there is a small plaza. From this small plaza, one climbs a series of stairs to the atrium gate, which is an arcade of three arches with decorations in relief. The atrium takes up most of the monastery grounds and is rectangular, measuring sixty meters long. The most elaborate feature of the atrium is the four chapels embedded in each of the area's four corners, constructed around 1550. They were used for processions, especially for the storage of the Host for processions, but they were also used as chapels to serve the many indigenous of the area in the 16th century. They are elaborately decorated with the Franciscan coat of arms, cords like those worn by Franciscan monks with tassels and other symbols. This decorative feature can be seen in other parts of the complex as well. In the center of the atrium, on the pathway between the main atrium entrance and the entrance to the church, there is an atrium cross. Most histories of