Next door to the post office is the Atik Mosque. This was once the oldest mosque in Ghadames, if not all of Libya. The original mosque on this site was built in 44 AH (AD 666) and, incredibly, survived until 1943, when it was destroyed by Allied bombing. The sanctuary is off-limits to non-Muslims, but from the door you can see the attractive row of arched pillars, running across the centre of the rectangular hall, and the mihrab.
