In July 2021 the Jomon prehistoric sites of Hokkaido and the northern Tohoku region of Japan were listed as UNESCO World Cultural Heritage. Ever since then I had wanted to visit and write about them, and recently the opportunity arose for me to go to and compile this report on the Sannai Maruyama Site, which was an especially large settlement among the 17 component places of the World Cultural Heritage and is the biggest Jomon site in Japan. On the day of my visit, I was able to speak with Mr. Yasuhiro Okada, who was involved in the large-scale excavation survey of the Sannai Maruyama Site, which began in 1992, right from the start and currently is director of the Sannai Maruyama Jomon Culture Center. Mr. Okada is also the author of some books I read before my visit. In addition, despite the poor weather forecast, it was a miraculously fine early morning, so we got our drone photography done and were fortunate enough to take some marvelous videos. Together with the text, I hope readers will enjoy viewing the videos of the Jomon site, which, viewed from above, appears just like a fairyland.