Нахтигаль
Part of Germany's plan to invade Poland, "Fall Weiss" (Case White), involved small groups of Germans dressed in "Räuberzivil" ("robbers' civvies" - inconspicuous, rugged casual clothing) crossing the border the night before and seizing key strategic points before dawn on the day of the invasion. The secret Abwehr battalion detailed to undertake these operations was given the euphemistic title of "Construction Training Company 800 for Special Duties". A group under the command of Lieutenant Dr. of "Abwehrstelle" Breslau, who later became commandant of the Nachtigall Battalion, the first foreign legion of the "Wehrmacht", was instructed to prepare the way for the assault of the 7th Infantry Division by infiltrating the border. They were to capture a railway station at Mosty in the Jablunkau Pass in the Carpathian Mountains to prevent the destruction of the single-track railway tunnel which was the shortest connection between Warsaw and Vienna.