Regarding Constantinople 1453 there is plenty of information. The top picture is a nice diorama of the conquest where you have to the right the Genoese Galata neighbourhood and to the left the main Constantinople itself.
The remains of the original chain can still be seen in the museum.
Panorama style you can see a very beautiful and detailed painting of the main assault. I took several sequential pictures L-R so the detail can be seen more clearly.
The painting also shows some scattered materials like artillery baskets, guns and helmets which enhances detail.
Even today you can find remains of the walls of Constantinople everywhere. Even normal houses or shops used them for its own benefit.
Istambul is a great place for holidays speciallly for the History lover and the Constantinople siege of 1453 is a great wargaming subject. I hope to have contributed for that in this series of posts.