How did Northern Europe geography and technology affect each other in the course of Europe's history

Northern European geography and technology influenced each other mainly by being in close contact, and also the fact that very often most of the region was under a single ruler. The interchanging of information and technologies, as well as mutual support, was a must in this harsh part of Europe, so whenever something was discovered in some part, it was very quickly known and used in the other parts. The fact the lot of time a single country had the power over the other ones, just made it easier for sharing technologies.