Why were stone and brick used more often in eastern sections of the Great Wall?

The construction of the Great Wall of China varied significantly across its length, primarily due to the local availability of building materials.12

In the western regions, where the landscape is dominated by deserts, the wall was typically constructed using simple materials such as rammed earth and adobe. Conversely, in the eastern sections, builders had access to different resources, allowing them to face the ramparts with stone and brick. This choice of materials in the east facilitated the inclusion of more complex secondary structures, such as arched doors, crenellated platforms, and drainage systems, which were essential for the wall's defensive functionality.12