Since prehistoric times, a religion of nature worship has been practiced in the mountains of the Kii Peninsula, in Western Japan. The sites and pilgrimage routes associated with this religion were registered as a World Heritage site in 2004. The network of pilgrim routes is known as the Kumano Kodo. One of the most important is the Iseji Route, which runs from Mie Prefecture to the three grand shrines of Kumano, in Wakayama Prefecture, in the south of the Kii Peninsula.