The entire forum contains ruins from hundreds of buildings, mostly government buildings and temples. After the collapse of Rome, the few people who stayed around largely ransacked the place, stripping the magnificent buildings nearly to rubble. The area soon became abandoned and covered in the debris of future generations. You can see a church that was built on what they thought was ground level during the middle ages. After the area was excavated during the nineteenth century, the church was marooned, with a doorway several floors above the ground. They do a good job of explaining what was what, what happened in the various buildings and processional roads. The temple of the vestal virgins is a good example, with nearly all the virgins' statues (sans heads) still there, as you can see in the photo. These virgins, by the way, were the most important women in Rome, ranking just below the empress, but in return for their high status they had a pretty boring life. They entered the temple when they reached puberty, spent ten years learning the arcane rituals that they practiced alone inside the temple, then ten years performing these rituals, then another ten years teaching the rituals to the next crops of virgins, after which they retired. As the name implies, they remained virgins forever, and for those who broke this rule, they were buried alive in a tomb that is now underneath a big traffic circle in modern day Rome, which is kind of creepy.