Yeah, the adjective doesn't exactly work, but whatevs.
When I was returning from Berlin, I ended up being routed on a totally different train than had been originally planned. The route took us through the German state of Niedersachsen, which English speakers would call Lower Saxony. This also borders the Netherlands (Niederlande).
It was striking how flat the land was around there. I guess calling it "lower Saxony" in German makes sense; even though this is a northern state, the land is low.
I was mulling this flat scenery over as I was huffing and puffing while biking in my German home state, Rhineland Pfalz, which is a forested German state with lots of hills (as well as some mountains). The bike ride was difficult for me since I've been rather physically inactive because of class and being sick (as a result of allergies, not from being in air conditioning!).
I was thinking about how it's such a part of culture in the northern areas of Europe for people to bike. Then I envisioned the topography of the Nieder-regions (har har) and realized why: it's flat there! They cheat! Of course it's easy to bike if there are very few hills ;)