The sense of wonder and admiration experienced by individuals who witness a striking sight, whether natural or man-made, has long been regarded as playing a role in the acquisition of knowledge. Both Aristotle and Plato regarded wonder and admiration (thaúma), sparked by something seen, as the origin of philosophical thinking. In the Middle Ages, theological writers considered the way in which admiration and, specifically, the state of rapture it engendered, helped the Christian experience devotion to God. What happened when a beholder was filled with admiration upon encountering a magnificent building was addressed in discussions of magnificent patronage from at least the thirteenth century. The present Note investigates how Alberti's reflections on magnificence and admiration informed his theory of aesthetic design in De re aedificatoria, completed in the 1450s. It proposes that Alberti redefined what makes a building admirable or 'magnificent' and also understood 'beholding in admiration' to be an active mode of looking. Therefore, his views on magnificent architecture were subtly different from those of Pope Nicolas V, in particular. By considering Alberti's theory of aesthetic design as a reflection on magnificence and admiration, additional light is also shed on his confidence in the protective power of beauty and his design recommendations for the temple.