The abundance of streams in Edessa led sensibly to an abundance of mills and other machinery to exploit this renewable power. Scattered around this open-air 'museum' are two flour mills, a water mill, fulling machinery and a sesame mill, where you can still see tahini ground today (€2 entry, open 10am to 4pm Tuesday to Sunday). There's also a modest aquarium housing fish endemic to the area (€2, open 10am to 6pm, closed Tuesday).
The 'museum' lies to at the southern end of Edessa Waterfalls Park.