The Church of Saints Sergius and Bacchus (Abu Serga) in Coptic Cairo is one of the oldest churches in Egypt — traditionally dating to the 4th century, with the current structure largely from the 10th-12th centuries. Its significance lies in the crypt beneath the nave, a cave where the Holy Family is traditionally said to have sheltered during their flight from Herod into Egypt. For Coptic Christians, it is among the holiest sites in the country.
The church is a typical Coptic basilica plan: a nave divided by two rows of marble columns, a screen of carved wood separating the sanctuary, and an apse with icons. The crypt is accessed by a narrow staircase at the western end; it floods seasonally with Nile water, which has been seen as sacred. The church is usually open to visitors during daylight hours within the Coptic Cairo compound.