Ben Ezra Synagogue, Originally this was the Church of St. Michael the Archangel, but after being closed by the. khalif al-Hakim it was purchased by the Jewish community. Much of it was rebuilt in the late 19C, although the basic fabric is original.
During the rebuilding a hoard of several hundredold Hebrew manuscripts was uncovered. These are known as the Geniza documents, and provide a unique source for the history of the period from the early 11—16C (many are now in the BL).