Visit the Complex of Religions in Old Cairo.
In this place, you will see the mosque (Amr Ibn Al-Aas Mosque), the first mosque built in Egypt, and churches, including churches for the Holy Family's journey to Egypt and the Jewish synagogue.
From wiki
Coptic Cairo is a part of Old Cairo which encompasses the Babylon Fortress, the Coptic Museum, the Hanging Church, the Greek Church of St. George and many other Coptic churches and historical sites. It is believed in Christian tradition that the Holy Family visited this area and stayed at the site of Saints Sergius and Bacchus Church (Abu Serga)
