Cologne, or Köln in German, is a big city in Nordrhein-Westfalen.
To get out of Cologne to the South the best possibility is to go to the Verteilerkreis Süd, a big roundabout where all vehicles that are heading for the motorway to the South or West are passing by. There is also a petrol station beside it and a traffic light where one can ask people for a lift.
On the motorway ring around Cologne, to the west of the city, there's the motorway service area Köln-Frechen, Germany's busiest service station. There you can get lifts to the Netherlands and Great Britain from one of around 200 HGV's that are there in average.