Why has poland been vulnerable to invasion?

For starters, Poland is surrounded by large European countries who have historically been strong conquerors like Germany and Russia. Another is that there are no natural barriers like mountains, you can just enter with your army easily. Another is that it's full of natural resources so naturally people want to take them. Another is religion. It's catholic but is surrounded by Protestants and Orthodox Christians, so there you have it.

C4 i’m pretty sure