The idea of a migratory or mobile city is commonly used in science fiction. There are various kinds of migratory cities, which Carl Abbott explains with examples from various films. Abbott explains the plot of the films and how these cities came to exist in the stories. I learned a lot and agree with him on most of the points he makes about different types of migratory cities. However, I partially disagree with him when he discusses the Snowpiercer. He discusses how it lacks interaction with the outer world and is too small. While I agree that the train lacks trade, it still has quite a number of people and interaction among people within the train. Considering how ancient cities were smaller and traded less compared to modern cities, I believe the Snowpiercer can be considered a migratory city, just not the huge trading cities of modern times.