Belgium is famously flat. It's clichéd to say so, but yet I still find the flatness unbelievable. There doesn't appear to be even a molehill of variation in height. Flat land feels completely unnatural, eerie to me. I grew up in the Chiltern Hills where you went out the door and then up or down. The Flemish word for countryside is "platteland", which literally means "flat land". And it goes on for miles - right down to the Ardennes in the south of Belgium.
Here there are acres of land with verdant grass. Like Britain, the climate has plenty of rain and plenty of unpredictability. The fields are divided by ditches for drainage. Lines of trees, often poplars or Dutch Elms (different from English ones, nothing to do with the disease), may also serve as boundaries, as well as providing some protection from the wind.
It's often said that the Low Countries are fantastic for cycling, and there are certainly 1000s of bikes. But don't be fooled - the wind can blow very hard across flat land, making for very hard pedalling.