listen to a conversation between a student and his professor of European history. P: Oh, hello, Ken, aren\'t you a bit early? Isn\'t our appointment for three o\'clock? S: Yeah, sorry to surprise you, but if you have time, could we talk now? That way I can get to the library before it closes. They\'re closing early today because of the snowstorm that\'s coming. P: Sure, come in. S: I saw that documentary film you recommended about ancient Roman roads in Britain. Thanks for telling me about it. P: Yes, I thought it would help you prepare for your trip to Britain this summer. I remember you said you\'ll be visiting some Roman sites. So what did you think? S: Well, it said a lot of the same things that you were saying in class. Like before the Romans first arrived in Britain, there were no real roads. The Romans built paved roads so they could travel quickly across long distances. And for the same reason, they always made the roads straight, so they had to do things like drain marshes and cut down trees that were in the way, even tunnel through mountains. P: Yes, and building those roads led to some unintended consequences. For example, the local inhabitants started using the roads to reach places that they hadn\'t been in contact with before. So there was more trade. But in building these nice straight roads, the Romans were also providing their enemies with an easy way to attack them, which is partly what brought the Roman era in Britain to an end. S: But there\'s one thing that didn\'t get explained, and that\'s what I wanted to ask you. The Romans were in Britain for 400 years, but what happened to their roads after they left? P: Well, those roads were certainly built to last, but they did eventually fall into disrepair because the local people didn\'t have the engineering know-how to maintain them. In fact, there wasn\'t a good transport system in Britain again until the 19th century, when the railways were built, talk about being ahead of their time. So, to answer your question, things largely went back to the way they\'d been before. On the other hand, the story doesn\'t end there. An astronaut aboard the International Space Station took a photograph of Britain at night. You can see it online. The cities and towns are all lit up, and between them are brightly lit lines where the modern highways are. I think you\'ll be surprised by this photograph. It\'s like looking at an aerial photo of the Roman road network. And as for the roads that disappeared entirely, some of them are being found again. Now that we have advanced sensing systems that can scan what\'s under the ground.