here is the link to the photo by Piotr Skoczylas that I saw on 500px.com
I am really interested in finding out how he has done this or ideally point to a tutorial which explains the techniques using this in photoshop
Edit: I believe from reading the links in the post I marked as answer this effect is called double exposure. in an effort to appease the stackexchange police I am adding this so that anyone that comes across my question will know what I am referring to. I suppose the irony is that had I known it was called this I think I would have googled that and probably found it myself and not posted here asking.