Today I found this box in my attic, so I wanted to open it but in order to do so, I need to insert something in 6 slots in my box.



My grandfather constructed this box in WWII he was a very talented man so he created this strongbox, so there is no way to open it another way; you hit it you break the content, you heat it up and you will burn it. He left some clues on the box in order to remember the answers. Could you help me find them?



This is the picture engraved on the box.





I think he told me that there is something about that war that he will always remember, I think that was a clue as well.





The content will be revealed when the puzzle is solved.





If you have too much truble in solving the puzzle let me know! I will be happy to give out some hints! :D