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 that rock into the outspread wings of a condor in flight. Historians speculate the head of the condor was used as a sacrificial altar. A mummy was discovered in a small cave under the temple. A prison complex stands directly behind the temple and is comprised of human-sized niches and an underground maze of dungeons.