Millenia ago a ship crash-landed in this valley. The crew of the vessel integrated with the locals and used their ships replicators to produce food and supplies on a massive scale, allowing the nearby tribe to quickly overtake their neighbors. The location of the ship became the central, holiest site in a vast empire. Eventually the ship's reactor malfunctioned, and without the knowledge to maintain it the successors of the original crew were unable to fix it. By that time this society had become so dependent on the food and supplies from the ship that the knowledge for agriculture and other crafts were completely forgotten, resulting in widescale famine. It seems the inhabitants believed they were being punished by their gods and began sacrificing huge numbers of individuals to attempt to appease them.