I heard what sounded like a huge explosion from very far away?

They're probably making considerably more noise than someone in the next street would, plus there could be a wind or breeze blowing from the park to you.

Under the right conditions sound can be reflected and diffracted great distances.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.