The Monastery of El Escorial is one of the most important monuments in Spain. Located on the southeast slope of the Sierra de Guadarrama in the municipality of San Lorenzo de El Escorial (in the community of Madrid), the monastery was declared a World Heritage Site by UNESCO. It was built in the sixteenth century (between 1563 and 1584) and became the biggest building in all of Europe. The complex includes a royal palace, a basilica, a cemetery, a library and a monastery. The palace was the residence of the Spanish Royal Family, the basilica is the burial place of the Spanish kings, and the monastery is currently occupied by St. Augustinian monks. Also known as the Monastery of San Lorenzo El Real, or simply El Escorial, it was founded by monks of the Order of St. Jerome. The complex was designed by King Philip II and his architect Juan Bautista de Toledo. Subsequently, other architects joined the project, among whom include Juan de Herrera, Juan de Minjares, Giovanni Battista Castello, the Bergamasco, and Francisco de Mora. At the end of the sixteenth century, the monastery was considered the eighth wonder of the world because of its size, functional complexity and symbolic value.