Djerba's mosques look like small fortresses, which is more or less what they once were. Imghar, in the interior of the island, is one of the group of Ibadi mosques whose whitewashed walls, thick buttresses and low domes give them the air of a farmhouse that has been trained for war. Ibadism is a branch of Islam that predates the Sunni-Shia split, and it survives today mainly in Oman, parts of North Africa and here on Djerba, where it has shaped the island's culture for over a thousand years.
The mosques were built to serve a scattered farming community, with each hamlet, or menzel, having its own place of prayer, and some of them doubled as schools, courts and refuges. Walls are plain, with few windows, and the interior is a cool, dim hall of low vaults supported on heavy pillars, unadorned and quiet. The simplicity reflects a puritan tradition, and many mosques have a small minaret that looks more like a watchtower. Some have underground prayer rooms for use in summer heat, and many are still in use. Non-Muslims are usually not admitted to the interior, so respect the signs and enjoy the architecture from outside.
The ride across the island is flat and easy, along roads lined with palms, olives and whitewashed walls, past small farms and tiled houses. Surfaces are generally good, but the roads are narrow, and locals ride scooters without helmets and drive fast. The wind from the sea can be strong, and sand blows across the road in some places. Be careful at roundabouts, and in the heat of midday expect to see few people on the street. Djerba is small enough that every point is within an hour of any other, so you can ride a loop of several mosques in a day.
Fuel is easy, with stations in the main towns, and the island's capital, Houmt Souk, is the best place for repairs and food. Erriadh, fourteen kilometres away, is a larger village with cafés and a lively market. Try a plate of couscous with fish, or brik, a fried pastry filled with egg, followed by a glass of strong, sweet mint tea.
Spring and autumn offer pleasant temperatures; midsummer can be fiercely hot.