Library is modern -- the ancient wonder is sunken under the bay. Neat, but not fascinating. The catacombs were kind of neat, but again, not fascinating. Alexandria is a filthy town -- all of Egypt needs to work on their sanitation. It would be neat to dive on the undersea ruins of Alexandria, but I'm afraid the bay water is polluted just looking at the city itself.
Read Ockham's full Celebrity Silhouette cruise review