Still one of the largest pieces of architecture ever constructed, the Great Pyramid has long been the subject of wonder as to when it was built, by whom, and most importantly, why. The conventional explanation is that it was built during the reign of the Pharaoh Khufu by skilled Egyptian laborers as a funerary monument. In addition to pyramidology, Joseph Seiss was a Christian dispensationalist, a 19th century millennialist school of thought.