What architectural feature is used to create high ceilings in Gothic structures?

The flying buttress is a defining architectural feature of Gothic structures that enables the construction of high ceilings. This design element consists of external supports that transfer the weight and outward thrust of the roof and upper walls to a distant support, allowing for taller and thinner walls. Consequently, this structural innovation not only enhances stability but also provides the opportunity for large stained glass windows and intricate designs that characterize Gothic cathedrals. High ceilings contribute to a sense of verticality and aspiration in the architecture, creating an awe-inspiring space that encourages spiritual reflection. This is why the flying buttress is considered integral to achieving the monumental heights associated with Gothic architecture.

The other options, like balustrades, spires, and pediments, do not serve the same function as flying buttresses. Balustrades generally serve as decorative barriers, while spires are tall, pointed structures that can accentuate a building's height, and pediments are triangular sections above doors or entranceways that add to the overall aesthetic but do not provide structural support for height.