I first learned about the town of Luna while doing research on the fortifications in the Philippines during the Spanish era. Beginning in 1565, Spanish colonists built fortifications to protect themselves and their emerging settlements. They built fuerzas and baluartes all over the archipelago to ward off the attacks of pirates and invaders.
Among the most attractive baluartes that the Spaniards built is the 400-year-old cylindrical watchtower in Luna. Old photos show the deep groove around the inner rim and the quadrilateral notches.