Moss is a small industrial city on the eastern shore of the Oslofjord, about an hour south of Oslo by train. It is not a typical tourist destination, but it has a few things worth stopping for if you are passing through or exploring the Østfold coast.
The main cultural draw is Gallery F15 at Alby Manor, set in a handsome estate overlooking the fjord on the Jeløya peninsula. The gallery hosts rotating contemporary art exhibitions and the grounds are lovely for a walk. Jeløya itself is surprisingly green and scenic for being so close to town, with beaches and gentle coastal paths.
Moss also has a place in Norwegian history: the Convention of Moss was signed here in 1814, paving the way for Norway's union with Sweden while preserving the Norwegian constitution. The convention building still stands in the town centre. The Moss Jernverk and the old industrial quarter along the Mosselva river round out a pleasant half-day visit, and the ferry to Horten across the fjord connects you to the Vestfold side if you are driving south. Vansjø lake to the east is popular for summer swimming and kayaking.