At first I was going to say that based on the architecture of the column in the back, it looks like it's Roman, or roman inspired, I'd say. The structure is not an ancient structure at all. If you look at the wall you can clearly see that there's no way any ancient structure would look like that or would be made of those materials. Then the walls reminded me of a place I was last October. A simple Google search lead me to:

That is a sculpture named "The Torment of Marsyas", from the Department of Greek, Etruscan, and Roman Antiquities: Hellenistic Art (3rd-1st centuries BC), Museum of Louvre, Paris, France.
I agree with smiddy regarding the obsession that the WT has with Jesus of Nazareth not being crucified. I don't get it. I hope this shed some light.
My stance is that to me that's not relevant. If you believe or not in Jesus, how is his sacrifice affected by the position in which he was murdered?