Alexander the Great's tomb?
There was a place in Alexandria that the Arabs called “the Mosque of Ḏū ’l-Qarnayn” soon after the seventh-century conquests. Ibn ʿAbd al-Ḥakam (d. AD 871) places it “near the lebbeck trees at the imperial market” near one of the city's gates ...
(NB: Ibn ʿAbd al-Ḥakam identifies Ḏū ’l-Qarnayn with Alexander.)
It may have been revered by early Muslims. A man told ʿUrwah ibn al-Zubayr [while living in Egypt?] that he entered iḥrām at the mosque of Ḏū’l-Qarnayn when embarking on his pilgrimage. ʿUrwah did not object