Taishakukyo Gorge located on the border of Shobara City and Jinsekikogen-cho in the northeastern Horoshima Prefecture is a large-scale gorge with the total length of 20 km. It is one of Japan’s 5 Fine Gorges.  The gorge has the Onbashi Bridge, which is Japan’s largest natural bridge and is designated as a national Natural Monument. It is also said to be one of the world’s 3 largest natural bridges, as well as many limestone caves including the famous Hakuun-do Cave. Nature remains intact in this gorge.
Taishakukyo Gorge was formed by the Taishaku River having eroded the water-soluble limestone layer. The towering cliff of more than 100 m tall and the Onbashi Bridge, which is a huge rock with a large hollowed part in the center, are worth seeing as the figurative art objects that were created by natural power. The rare species of creatures such as Stereophaedusa costifera, a snail with a slender shell, inhabit in the gorge. This snail eats limestone to produce its shell.