Quick. When I mention Germany, what kind of landscape comes to mind? Mountains, the big rivers, castles on hills, Neuschwanstein (which falls into “all of the above”). And lots of trees, probably pines, pines on hills, that sort of thing. In other words, Bavaria, the Black Forest, Heidelberg, and similar sites. Actually, more of Germany is rather flat to rolling, while northwestern Germany is pancake flat. In part because it got pancaked by ice, and covered in river sediment after the ice ages ended. It is closer to Holland than to Bavaria in terms of topography, and can be forested, grassy, swampy, or all of the above at once.
This is a place were you have water castles, castles defended by complicated series of moats and marshy stretches. Until the 19th century there were also a lot of grave mounds, dating back to the neolithic and Copper and Bronze Ages, with Iron Age sites just for variety (and because some graves were re-used). Many of those have since been plowed flat, or had their stones liberated for monuments and building material. This is where brick gothic architecture dominates, because stone had to be imported. If you visit the extensive marshlands, the remnants of even greater wetlands and swamps, you can appreciate why this is called Low Germany. People became herders and traders because that was about the only thing they could do with the soggy landscape for quite a while.
The rivers tend to meander, especially the Elbe.
The region does have hills, but no mountains to speak of. The glaciers that came down from Scandinavia, and up from the Alps, flattened everything on the North German Plain, with a few notable exceptions. They left behind a waterlogged and lumpy landscape that was not well-drained until after the 1700s. This is where Charlemagne and the Saxons fought several times, where the pagans resisted conversion, where brick cities and trade dominated life. It is also the part of Germany that looked west to Britain and north to Scandinavia in language, economy, and culture. The dirndle is not worn up here. Instead there is a stronger Dutch influence.
One festival version of local costume. Note the man’s coat – not anything like you’d find in Bavaria or the Tyrol.
I suspect this tradition (seen below) dates to the mid-1800s, at most to the 1700s. Although the woman in the center could step into a Breughel-the-Younger painting and no one would blink.