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
German invasion of Belgium war on Germany at midnight on Central European time. Belgium severed diplomatic relations with Germany and Germany declared war on Belgium. German troops crossed the Belgian frontier and attacked Liège. The Battle of Liège was the first engagement in the German invasion of Belgium and the first battle of World War I. The attack on the city began on 5 August and lasted until 16 August, when the last fort was surrendered. The German invasion led the British to declare war and the length of the siege may have delayed the German invasion of France by Railways needed by the