Valletta City of Malta was built by the Order of Saint John. The city was named "Humilissima Civitas Valletta" — The Most Humble City of Valletta. (1566)
A very nice shot! I love this kind of historical place. Interestingly, the not-so-humble fortifications seem to be below the ground level; a very odd design considering the logistics of the day: most castles would be built on top of hills/mounds etc, otherwise they'd be vulnerable to enemy attack.
Actually Valletta city was built on a hill top (Scibberras Hill) facing the Grand Harbour. A very strategic place as all the attacks to Malta where by ships (at that time). The fortifications seem to be underground because I took the photo on top of the fortification itself. Regarding the name in origin it was Humilissima but after it was built with all its architecture it became known as "Superbissima" see wikipedia for more info.