Postcard issued by Wehrmacht depicting a German unit breaking into Sochaczew, on the way to Warsaw under the cover of armored car.
Interestingly Germans entered Sochaczew twice during September 1939. First time on day 9 of Fall Weiss (September 9, 1939) after which they were pushed out by Polish counterattack on 13th. And then again on September 15 after Polish troops withdrew as a result of heavy German artillery bombardment. Taken extensive damage shown in the picture, it may have been the second time.