The pinnacle is a conical or pyramidal architectural element that tops off the buttress.
At first glance, the pinnacle may look like am ornamental element, and it indeed adds decoration to the building; it also creates an illusion of height with its pointed shape. While the pinnacle plays an aesthetic role, it also has a structural function. Its weight creates a vertical force that counteracts the lateral thrusts of the flying buttresses, and it gives the buttress stability.