In between Arsenal Park and North Beacon Street there is a hill and at the bottom of the hill there is kinda a wooden area where you can find rabbits and chipmunks scurrying around. Yesterday, I saw an odd structure in that area; it appears to be some sort of archway. (possibly an archway of doom.)  I did not take a chance and walk through it for fear I would get sucked into some sort of vortex or that the archway was actually the teeth of a great beast waiting to clamp down on any unsuspecting people. Below is a picture of the object. Anybody have any idea what it is?