This Image of the Day is the answer to the November puzzler.
At first glance, the Daisenryo Kofun (alternately, the Daisen Kofun) looks like a forest on a hill. But underneath those trees lies a tomb so grand that it rivals the Taj Mahal and Egyptian pyramids.
Shaped like a keyhole, the burial site is surrounded by three moats and measures more than 300 meters (1,000 feet) wide and 450 meters (1,500 feet) long—twice as long as the base of the Great Pyramid. Supposedly built by about 2,000 men working daily for almost 16 years, the tomb is one of the largest in the world.
The Daisenryo Kofun is one of about fifty burial sites still intact today in the city of Sakai, near Osaka, Japan. Each kofun (which means “ancient grave”) varies in size and takes different shapes—but most often keyholes, squares, or circles. Kofun were popular in Japan between the third and sixth century, which is referred to as the Kofun Period.
The image above shows several kofun collectively known as the Mozu-Furuichi Kofun Group. The image of Sakai was acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite on October 11, 2017. This false-color scene includes green, red, and near-infrared light, a combination that helps differentiate components of the landscape. Water is black, vegetation is green, and urban areas are gray.
The Daisenryo Kofun is the largest in Japan, but little is known about what lies inside. One glimpse came in 1872, when a severe storm damaged the site and revealed a treasure-trove of valuables from inside—helmets, glass bowls, and clay figures known as haniwa. Because kofun are considered sacred religious sites, further archaeological research was prohibited. Even today, no one is permitted to go beyond the bridge over the second moat.
Kofun demonstrate a highly sophisticated funerary system, but also a represent the growth of social and economic hierarchies in a developing Japan. The flat, arable land needed to build a kofun was rare in mountainous Japan, and it was a commodity that only the extremely wealthy could afford. The Daisenryo Kofun is thought to hold Japanese Emperor Nintoku, but other kofun were built by non-royal, wealthy elites in Japan— a reflection of the country’s growing wealth in the era. Historians believe kofun are the first signs of a rigid social and economic structure emerging in Japan. Because of its historical significance, the Mozu-Furuichi Kofun Group is listed as a UNESCO World Heritage site.
NASA Earth Observatory image by Joshua Stevens, using data from NASA/METI/AIST/Japan Space Systems, and U.S./Japan ASTER Science Team. Story by Kasha Patel.