Cities all over the world have an underground network of trains running right beneath our feet, helping the public to travel around quickly and safely.But how did these underground networks begin, and how were they built?Find out the fascinating history of underground trains in this non-fiction book by Richard Platt. Collins Big Cat Progress books are specifically designed for children at Key Stage 2 who have a Key Stage 1 reading level, giving them age-appropriate texts that they can read, building their confidence and fostering positive attitudes towards reading. Text type: A non-fiction bookCurriculum links: History; GeographyThis book has been quizzed for Accelerated Reader.