This is an attractive forest marathon on the outskirts of Oslo, Norway. They are also doing a half in recent years. Both are easily accesible from the last stop of a metro line from the middle of Oslo. See english at https://nordmarkaskogsmaraton.no/about-nordmarka-forrest-marathon/ It's coming up this Saturday. Start is from the arena and clubhouse of a combined football and ski club (Lyn) with ample parking in the area. It's very easy to get to if you are in the Oslo area or even if you fly to Oslo airport.