As the Egyptians believed that the unmovable area the stars circled was heaven, the pyramids were built to align north with a single, perfectly aligned vent. In King Khufu's Pyramid, the shaft itself, built into the structure, started at the chamber of King Khufu and ends at the outside. The shaft was built at an angle, so it could always sight The Indestructibles. The Egyptians built this vent in the pyramids in order to ensure a perfectly aligned path towards heaven (although recent researches have shown them not to be completely perfect). Hancock and Bauval claim these inaccuracies mean that the Great Pyramid and by extension the Sphinx were built "c". 10,500 BC, a suggestion not widely accepted.