The center of Osgiliath(ne and nw)

You are walking over the great island that forms the center of Osgiliath. A mighty stronghold this must have been in days of old, but only crumbling stone remains now, a mere ghost of the past.
A mighty tower rises high above you here. It is still in good shape although there is a large chunk of stone lying in front of the entrance, blocking any passage in.
A foul brown haze covers everything.
The only obvious exits are northeast and northwest.