McLean Mill is the strongest heritage sight in Port Alberni: a preserved sawmill complex from the age when cedar and Douglas fir drove the valley's economy. The site keeps original mill buildings, logging equipment, and the rough practical feel of an industrial camp rather than turning it into a polished museum set.
Check opening days before you go, as the site has had changing operations over the years. When demonstrations are running, it is one of the better places on Vancouver Island to understand how logging shaped the towns behind the beaches.