The monastery of Santiago Apostol in Ocuituco dates from 1534 and is the first Augustinian monastery on the American mainland, with Fray Juan de Zumárraga celebrating its first mass in 1534. It served as not only an evangelization center, but also a training center for monks. The monastery has a vault in the lower floor of the cloister which used browns, whites and greens in its figures. The chapel for pilgrims is closed, unlike the other monasteries, but the rest of the complex is open to visitors. There have been some modifications to the buildings since they were built, but one well-preserved element is its 16th-century stone fountain, the oldest of all the monasteries of the World Heritage Site. This fountain is a replica of one found in the Alhambra in Córdoba. It features six sandstone lions facing the center, which were sculpted by indigenous craftsmen. Located on the outside of the cloister, there is another fountain that used to be known as the Fountain of the Mermaids (Fuente de las Sirenas), but it has badly deteriorated. Both provided the community with water which flowed to them from Popocatepetl.