Teacher:Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Teacher: Now, understand the problem? Solve this instance: Context: When construction works finished on 4 December 1915, Leipzig Hauptbahnhof had become one of the world's largest railway stations with 26 platforms.
Question: When was the opening of Leipzig Hauptbahnhof?
Student:
1915