Denise and I stayed in a hotel made up of houses running between the
back wall of the Hagia Sophia and the land wall of the Topkapi Palace.
On closer inspection the iron plates are a least 3mm thick and the
rear of the portal has been block up.
Note the circular gun ports, one just below the parapet and the second
a little over half way down the tower face. The crenels on the flanking
walls have been filled in with red bricks.
Note, the door which would have led to the wall walk. These towers
are amongst the tallest wall towers of the complex.
The
Defences of Constantinople