Q: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Between the German invasion of Poland on 1 September 1939 and the Anglo-French declaration of War against the German Reich on 3 September 1939, the entire city (a total of 120,000 people) was evacuated, like other border towns as well. Until the arrival of the Wehrmacht troops mid-June 1940, the city was, for ten months, completely empty, with the exception of the garrisoned soldiers. The Jews of Strasbourg had been evacuated to Périgueux and Limoges, the University had been evacuated to Clermont-Ferrand.
A:
Who invaded Poland on 1 September 1939?