- The Mongols built siege weapons specifically designed to breach the Great Wall.
- The Mongols learned to use strategies to bypass the Wall, such as bribing or allying with the locals.
- The Mongols adopted advanced military technologies and tactics, such as superior cavalry and archery skills, which allowed them to defeat the Chinese armies in battle.
- The Mongols expanded their territory through a series of successful military campaigns, eventually overwhelming the Chinese forces and reaching the Great Wall.
Therefore, the Great Wall proved unsuccessful in keeping the Mongols out due to the Mongols' military innovations, adaptability, and determination.