After our pleasant stay in Rothenburg, we knew that the Cologne Cathedral was next on our must-see list. However, upon looking at the map, we decided to make a quick detour to Luxembourg City, Luxembourg, because why not? If a brief stop in Luxembourg, which wasn’t incredibly out of the way, meant seeing an additional country, then we were game. We also read that the cheapest gas in all of Europe could be found in Luxembourg. As we sluggishly drove our RV through the rolling hills between Western Germany and Luxembourg, we nervously kept an eye on the dropping gas…