The "Sekelskiftet" or "Turn of the century" monument was a private donation to Halden to commemorate 100 years of independence in 2005. Though the monument itself was unveiled in that year, the site around it has remained untidy until 2008 for 1d10tic reasons of local politics. (See http://www.ha-halden.no/artikkel.asp?Artid=179736 for an article on the local paper.) Finally, the area around it is tidier, with a play area, moorings for small boats, and plans for fishing for handicapped people. It is next to the Tistasenteret shopping centre, if you want to keep the family busy while taking a quick, 1d10tic cache
To find the cache, first visit these coordinates that take you to the monument. Look through a "split" or vertical crack in the monument across the river Tista. Centrally through the split you see a mooring post on the far bank. (Just to the apparent left of a lifesaver on your bank.) Are there lots of people watching you? Do you feel like an 1d10t yet?
You goal is behind the post you can see across the river. You can cross to the cache on the railway bridge to the right of the monument. Alternatively, it is much quicker simply to cross the river by boat, or swim :)
The cache is a normal smallish plastic box in a dark bag by the river's edge, in a direct line from split to post to bank. Once you have found the monument, you can find the cache without a GPSer (because to carry it in your swimming shorts doesn't look good)