Editing Hagia Sophia (section)

===Upper gallery===
[[File:Istanbul - Hagia Sophia - slope to first floor.jpg|upright|thumb|left|Slope leading to the upper gallery in the Hagia Sophia]]

The upper gallery, or [[matroneum]], is horseshoe-shaped; it encloses the nave on three sides and is interrupted by the apse. Several mosaics are preserved in the upper gallery, an area traditionally reserved for the Empress and her court. The best-preserved mosaics are located in the southern part of the gallery.

The northern first floor gallery contains [[Runic inscriptions in Hagia Sophia|runic graffiti]] believed to have been left by members of the [[Varangian Guard]].<ref>{{Cite book |last=Mel'nikova |first=Elena A. |url=http://worldcat.org/oclc/1233690226 |title=A New Runic Inscription from Hagia Sophia Cathedral in Istanbul |date=2016 |publisher=Institute of World History, Russian Academy of Sciences, Moscow |oclc=1233690226}}</ref> Structural damage caused by natural disasters is visible on the Hagia Sophia's exterior surface. To ensure that the Hagia Sophia did not sustain any damage on the interior of the building, studies have been conducted using ground penetrating radar within the gallery of the Hagia Sophia. With the use of [[ground-penetrating radar]] (GPR), teams discovered weak zones within the Hagia Sophia's gallery and also concluded that the curvature of the vault dome has been shifted out of proportion, compared to its original angular orientation.<ref>{{Cite journal |last1=Yalçıner |first1=Cahit Çağlar |last2=Kurban |first2=Yunus Can |last3=Altunel |first3=Erhan |date=May 2017 |title=Research using GPR into the cause of cracks and depressions in the floor of the gallery of Hagia Sophia Museum |journal=Construction and Building Materials |volume=139 |pages=458–66 |doi=10.1016/j.conbuildmat.2017.02.036 |issn=0950-0618}}</ref>