Detailed Instructions: In this task, you're given a context, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both context and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the context or linked information.
Q: Context: Adair's first major battle was in the pursuit of the retreating German Army to the Hindenburg Line. Link Information: The Hindenburg Line (German: , Siegfried Position) was a German defensive position built during the winter of 19161917 on the Western Front during the First World War. The line ran from Arras to Laffaux, near Soissons on the Aisne. Answer: The line ran from Arras to Laffaux, near Soissons on the Aisne
A:
How long was the fortification that the German Army retreated to?