The most prominent building in Acre's old city, recognisable by its green dome and graceful minaret. Ahmad Pasha al-Jazzar built it in 1781 on the site of a Crusader cathedral, using columns and stone plundered from Caesarea and other ancient sites — you can see them in the courtyard, a visible accumulation of previous civilisations.
The interior is cool and elegant, with marble from Roman ruins and frescoes imported from Constantinople. Beneath the courtyard are Ottoman water cisterns (open to visitors) of remarkable engineering. Non-Muslim visitors are welcome; remove shoes and cover heads. The mosque also houses a relic claimed to be a hair from the Prophet Muhammad's beard, brought here from Istanbul.