The main room (cella) contained the god to whom the temple was devoted, as well as a table for supplemental gifts or libations and a tiny altar for incense. A chamber or rooms behind the cella were used by temple attendants to store equipment and offerings. Other rooms may have been used for sacrificial rituals or as meeting places. The whole was usually surrounded by a peristyle garden. A Roman temple was built on a podium that raised it above ground level. This allowed for ventilation and also made it possible to place other buildings on either side without interfering with the view from the road outside. The podium was often shaped like a cube or a rectangle, with each corner capped by a large stone. The walls of the temple building were made of wood or marble, but most often brick. There were several rooms within the temple complex: the atrium, which served as an entrance hall; the propria, which was used by priests living on site; and the sacra, which contained objects sacred to the gods. Each temple had its own particular layout, but generally they were similar to one another. People traveled long distances to visit these temples for prayer and sacrifice. They were located near roadsides or in central locations within their respective cities, so that travelers could stop by them before heading home. Many survived today because they were converted into churches during the early Christian era.