Upvote:4
Out of the list of images in the question, some can be found on this site, which provides some descriptions of the photos. One of these is identified as the 'Golden Gate' of (then) Constantinople. The Wikipedia entry says this about the Golden Gate:
It was the main ceremonial entrance into the capital, used especially for the occasions of a triumphal entry of an emperor into the capital on the occasion of military victories or other state occasions such as coronations.
These military victories became much fewer, and finally:
With the progressive decline in Byzantium's military fortunes, the gates were walled up and reduced in size in the later Palaiologan period, and the complex converted into a citadel and refuge.
The Palaiologan period was the last period of Byzantine rule, so the premise of the question is off. The gates were actually walled in by the Byzantines as a defensive measure at a time when Constantinople was more often the target of attack. The Ottomans did not close this gate in.