A 486-meter-long giant tomb located in the southern part of Osaka Prefecture. It is one of the world’s three largest tombs along with the Great Pyramid of Khufu in Egypt (spanning 230 meters) and the Mausoleum of the First Qin Emperor in China (350 meters). Daisen Kofun is estimated to have been constructed over a period of 20 years in the fifth century. The Mozu Tombs, consisting of the Daisen Kofun and many other megalithic tombs in the surrounding areas, were designated a UNESCO World Heritage Site. The aerial view of the Daisen Kofun reveals its unique keyhole shape, square at the front and rounded in the rear. “What does this shape imply? Is it some kind of a symbol or code?” wondered Ritsu. He came here to find out but only discovered that one cannot see the whole site from a close proximity.