O-ita Prefecture is famous for its hot springs, particularly those in and around the city of Beppu, known as the 'hells', or jigoku. Many are of tourist interest only and cannot be used as onsen (notably the Blood Pond Hell (reddish water) and the Oniyama Hell). The city's ryokans and public onsen are amply supplied by the same volcanic source. Visitors particularly relish the effects of burial in steaming hot volcanic sands.