Various lists of the Wonders of the World have been compiled over the years to catalogue the most spectacular man-made constructions and natural things in the world.The Seven Wonders of the Ancient World is the first known list of the most remarkable man-made creations of classical antiquity, and was based on guide-books popular among Hellenic sight-seers. The number seven was chosen, as the Greeks believed that it represented perfection. Many similar lists have been made,including lists for the Medieval World and the Modern World.