The Temple of the Condor in Machu Picchu is a breathtaking example of Inca stonemasonry. A natural rock formation began to take shape millions of years ago and the Inca skillfully shaped the rock into the outspread wings of a condor in flight. On the floor of the temple is a rock carved in the shape of the condor's head and neck feathers, completing the figure of a three-dimensional bird. Historians speculate that the head of the condor was used as a sacrificial altar. Under the temple is a small cave that contained a mummy. A prison complex stands directly behind the temple, and is comprised of human-sized niches and an underground maze of dungeons. According to historical chronicles that documented similar Inca prison sites, an accused citizen would be shackled into the niches for up to 3 days to await the deliberation of his fate. He could be put to death for such sins as laziness, lust, or theft.