The thing that attracted me at this place was the heavy fortifications that are kept. It is obvious that this had an important part in defense: the fact that is a harbor but also has a citadel on a mountain top are enough reasons.
The city is a nice one. As an advice don't climb the mountain to the citadel unless you are in a really good shape ... although it looks close is really far and hard to get there, and you have to pay also 2 euros to be allowed to get there. From my point of view it was a mistake because after we got there really tired we just saw the city from that height, which looks great and saw some walls of the old citadel ... nothing really spectacular so climb only if you really want to get there :D.
As a negative aspect we sit on a terrace to eat something and the service was really terrible, they served us really really late ... so be prepare for the worst from this point of view :).