OK - so this isn't a Bell Tower, but it is one of the many sentry posts strategically built into the wall so that guards could see far out into the ocean, long before any pirates could even carry out an attack.

This is one of my favorite pictures. Where once upon a time this very point may have been witness to many a bloody fight, it's now a very tranquil, beautiful spot where even a bird (at the very top of the post in this picture) has found repose.