Intihuatana stone in Machu Picchu

The Intihuatana stone is one of many ritual stones in South America. The Spanish did not find Machu Picchu so the Intihuatana Stone was not destroyed as many other ritual stones in Peru were. These stones are arranged to point directly at the sun during the winter solstice. Intihuatana also is called "The Hitching Point of the Sun" because it was believed to hold the sun in its place along its annual path in the sky. At midday on March 21 and September 21, the equinoxes, the sun stands almost above the pillar—casting no shadow at all. Researchers believe that it was built as an astronomic clock or calendar.

The Intihuatana stone was damaged in September 2000 when a 450 kg (1,000-pound) crane fell onto it, breaking off a piece of stone the size of a ballpoint pen. The crane was being used by a crew hired by J. Walter Thompson advertising agency to film an advertisement for a beer brand. "Machu Picchu is the heart of our archaeological heritage and the Intihuatana is the heart of Machu Picchu. They've struck at our most sacred inheritance," said Federico Kaufmann Doig, a Peruvian archaeologist.

Resource: wikipedia.org