Osowiec Fortress Museum. <a href="https://en.wikipedia.org/wiki/57_mm_anti-tank_gun_M1943_(ZiS-2)" class="extiw" title="en:57 mm anti-tank gun M1943 (ZiS-2)">57 mm anti-tank gun M1943 (ZiS-2)</a>
<a href="//commons.wikimedia.org/wiki/User:Henryk_Borawski" title="User:Henryk Borawski">Henryk Borawski</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>