The castle of Saint George was originally built by the Venetians but was extensively renovated by Ali Pasha in the early 1800s. It is roughly triangular and had its own moat (though it survives only along the west side). The east side (towards the sea) has irregular, indented walls that stood directly on the shore. The walls stand to the original height, but the fort itself is inaccessible. Ali also surrounded the city with a rampart and a moat over two kilometers long. Both of these defensive constructions have vanished but their course can still be traced since a cycle path occupies much of moat. Just follow Nikopoleos street towards the north. When you see the road sign to Ioannina, turn left and then immediately right onto the cycle path.