Cairo's medieval city walls

There are places in Cairo, and indeed everywhere in Egypt, where the past can be seen poking through the surface, like this medieval tower in a parking lot:
After seven hundred years of debris were excavated, in order to construct a tunnel and a park, this part of Cairo's city wall, constructed by Saleh al-Din, was exposed:
Tip: click here!


Objective of visit:
To add the newly exposed sections of the city wall to the existing maps of medieval Cairo.
Date of visit:
  Fall 1998 and spring 1999.
Fellow visitors:
  Nicholas Warner.
Most of the results of this project were published in de Annales Islamologiques 1999; 33: 283-305 (IFAO, Cairo).
Approximate position and date of the site:   Both north and south of Sharia al-Azhar (the road on which the famous al-Azhar mosque is situated), between the crossing with Sharia al-Mansouria and Saleh Salem (the road to Cairo Airport), in the eastern part of Cairo. The walls were built at the end of the twelfth century. This work was started by Salah al-Din Ayyub, ruler of Egypt at the time and famous for his defense against the Crusaders.
Short description of the site:   The walls and towers are built of large stone blocks, many of them re-used from temples and other ancient structures, like the pyramids. They are purely defensive in lay-out, with narrow corridors, crenellations and arrow-slit windows. It is remarkable how several of the latter face inside, towards the city, rather than the outside. Over the centuries large parts have been destroyed, covered in debris and trash or built over by later buildings. The parts that were visible at the time have been studied comprehensively by Creswell in 1952 and only now and again additional parts become available for planning and research.
Additional remarks:
This work would not have been possible without the kind help of the Aga Khan Trust for Culture and the American Research Center in Egypt as well as several individuals.