Irie Shell Mounds (Toyako Town) form a historic site at which one can learn how people living in the area 3000 to 5000 years ago went about their daily lives. Shells discarded by people of that age, bones of mammals on land such as Ezo shika deer, and bones of sea creatures such as dolphins have been found there. At the entrance, there is a very big, transparent show case showing the old earth layers. Also a different shell mound site, Takasago Shell Mounds, isn't far from here. Moreover, there is a paid museum 'Irie Takasago Shell Mounds Museum' which houses important items discovered in the area.