The slumped hill on the background is the Kemmelberg, a 156m high hilltop dominating the area. The pleasant scenery hides the fact that under it, there's a gigantic bunker complex built by the Belgian Army in the fifties. This command bunker was to be NATO's nerve center for the Benelux (Belgium-Netherlands-Luxemburg) in case of a Soviet invasion during the Cold War. It was in use till 1995, and is scheduled to open this very fall as a tourist attraction, much like the UK's underground facility in Troywood, Scotland.
As much as I like the Heuvelland (literally Hill Country), I still prefer the Ardennes for hiking, a favorite pastime on those rare occasions when there is time. Scheduled for this fall is a trek with some good friends in Belgium's "extreme" south, along the Semois river. For those who would like to check out the area, I recommend the places on this map.