A view of the Great Mosque in Sana'a, Yemen. Reputed to have been ordered by the Prophet Muhammad, it was built around 705-15 by the Ummayad caliphs. Parts of it are said to come from the Himyaritic era from Christian and Jewish places of worship. It was extended and restored by the Ismaili Queen Arwa ibn Hamad in 1130. Photo: Christine Osborne.