Greåker

Greåker has been a site for diverse industry for decades, most notably in the area of paper production.

is Nordic Paper's kraft paper mill by the Glomma river, which is the continuation of over a hundred years of various wood processing works (e.g. Greaker Cellulose, Greaker Industrier).

It was one of several fortresses built along the Norwegian/Swedish border during this period, in preparation for a potential war between Norway and Sweden.

During World War II, the Germans attacked the fortress, coming across the river Visterflo, which unites with its source, Glomma, again at Greåker.

the fortress is in poor condition, and used as a look-out point over Fredrikstad and the southern parts of Sarpsborg.