What structural elements are prominent in the Markets of Trajan?

The Markets of Trajan are celebrated for their innovative use of barrel vaults and cross vaults, which play a vital role in creating spacious interior areas and enhancing the building's structural integrity. Barrel vaults are formed by extending a simple curve across a longer distance, while cross vaults, created by the intersection of two barrel vaults, effectively distribute weight and open up large spaces that can accommodate various functions.

This architectural strategy allowed the Markets of Trajan to become one of the earliest examples of a multifunctional commercial complex in Rome, serving as a marketplace, administrative center, and a hub of social interaction. The use of these vaults exemplifies the Roman mastery of concrete and masonry techniques, showcasing their ability to construct grand, durable structures that could support significant loads while allowing for artistic aesthetic.

In contrast, while pillars and arches (another significant architectural element) can indeed be found in various structures of that period, they do not define the Markets of Trajan as prominently as the vaulting techniques. Bowstring trusses and cantilevers, as well as steel girders and glass facades, are concepts and materials that belong to much later architectural movements, failing to represent the Roman architectural vocabulary used in this specific context.