The black passage, or Skifa el-Kahla, was once the only entrance to the town. It dates back to the early ages of the town, but had to be rebuilt after being blown up by the Spanish in 1554. The passage is not only visually attractive, but also perhaps the best explanation to the patterns of Tunisian sea ports. Travelling around the country, you cannot avoid noticing that most sea ports are set in a hundred metres or so from the sea. Only very rarely are the towns built along the shore. The explanation for this is piracy and foreign navies. Each town was almost like a state and had to defend itself, and by placing the town in from the shore, the seaborne invaders was stripped off the advantage of their ships. They had to leave their ships, and suddenly they were the weak ones standing in front of high city walls. Mahdia was not built like this, and was a piracy stronghold for centuries. Their defence was therefore city walls thicker than usual. Yet, this was not enough, and since the walls were brought down by the Spanish in the 16th century, Mahdia has mainly been a peaceful fishing port.
