France–Germany relations of the further integration of the EU. They are sometimes described as the "twin engine" or "core countries" pushing for moves. A tram straddling the Franco-German border, across the river Rhine from Strasbourg to Kehl, was inaugurated on the 28th of April 2017 symbolising the strength of relation between the two countries. Both France and Germany track their history back to the time of Charlemagne, whose vast empire included most of the area of both modern-day France and Germany – as well as the Netherlands, Belgium, Luxembourg, Switzerland, Austria, Slovenia, and northern Italy. The death of Charlemagne's son Louis the
France–Germany relations the mood in France, and plunged Germany into economic hardship and violent internal convulsions and upheavals. From 1933 under Adolf Hitler, Germany began to pursue an aggressive policy in Europe. Meanwhile, France in the 1930s was tired, politically divided, and above all dreaded another war, which the French feared would again be fought on their soil for the third time, and again destroy a large percentage of their young men. France's stagnant population meant that it would find it difficult to withhold the sheer force of numbers of a German invasion; it was estimated Germany could put two men of