One of the most important rivers in Europe, the Rhine, originates in Switzerland where the Vorderrhein and Hinterrhein rivers join. The flow is northwards to Lake Constance after which it flows westwards before turning North-East, where it enters the north sea through the delta region of the Netherlands. Nine countries are included in this one basin. The Rhine is one of the busiest water ways in the world and dense road and railway systems line its course. Many industries make use of the river but after a damaging chemical spill in 1987 the Rhine Action Plan was developed to ensure good ecological status for wildlife and river users.