The walls of Rabat encircle and protect the Medina, the historic center of the city. If you decide to take a train there, go down Mohamed V Avenue, past the central post office, and you'll be at the walls in no time. You can see that they're building the first metro line in Morocco, which is a huge project that will connect Rabat Salé Bou Regreg across the river. The doors each have a different name, and were excavated gradually with the increase in traffic and the population. The first wall dates back to the Almohad dynasty in the late 12th century. It measures more than eight feet high and two feet deep.