I live very close to the northern limit of the Roman Empire. The boundary is called Limes or limit. A whole bunch of Romans had to walk from Italy to get here to defend the border and squabble with what were then Germans.
I have been to Italy by car, by train, and by plane. I have never walked, but occasionally try to imagine what it must have been like for the poor bastards that had to way back when.
I went to war, but it was a comfortable war by comparison. I flew in a 707 and was served by attractive flight attendants. I'm sure that I was in love by the end of the flight, but never saw the girls again. I doubt even officers in the Roman army were served. But, they did have to haul their wine from home, which resulted in an impressive road network...even across the Alps.
Some smart guy decided that it was easier to carry a few vines and plant them along the Rhine River. The Roman army left a lasting impact on the land, laying the foundation for a whole lot of hangovers.
Modern-day armies act accordingly and take their culture with them. Of course, they do this with ships and aircraft. The modern-day equivalent of wine would be fast food establishments, brought by invading armies to succor their own but to share with the lucky invadees.
Wine has been cultivated for thousands of years in Germany; I doubt that McDonalds and Pizza Hut will be around in Kabul in the distant future.
Prior to writing novels, the author enjoyed a multifaceted career: from decorated combat aviator to advertising professional to global communications director of a major consumer brand. He has traveled the world and met sports, film and television stars, political leaders, and royalty. He graduated from Middlebury College, is married, lives in Germany, and has two grown children.