In what way does the Elbe River represent the connection between Britain and Germany in the novel, The Aftermath?

The Elbe River represents the connection between Britain and Germany. When Stefan explains to Lewis, for example, that “It flows into our Nordsee,” he asks if it is “Your North Sea?” (20). Lewis clarifies: ‘It’s the same sea in the end’ (20). It therefore serves as an example of how Lewis sees beyond the boundaries set between the British and the Germans due to the war as penetrable, and how he sees the potential for harmony and unity as they progress towards a better future.