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
Developed country Terms linked to the concept "developed country" include "advanced country", "industrialized country", "'more developed country" (MDC), "more economically developed country" (MEDC), "Global North country", "first world country", and "post-industrial country". The term industrialized country may be somewhat ambiguous, as industrialization is an ongoing process that is hard to define. The first industrialized country was the United Kingdom, followed by Belgium. Later it spread further to Germany, United States, France and other Western European countries. According to some economists such as Jeffrey Sachs, however, the current divide between the developed and developing world is largely a phenomenon of the 20th century.