What stood in the way of the mongols and other invaders that wanted to raid the Chinese?

The Mongols and other invaders faced significant challenges when attempting to raid China, primarily due to its vast and fortified territories, including well-defended cities and complex military structures. The Great Wall of China served as a formidable barrier against invasions, while the well-organized Chinese military, with its advanced weaponry and tactics, posed a serious threat. Additionally, the Chinese landscape itself, with its mountains and rivers, complicated invasion efforts. These factors collectively made large-scale raids difficult and often resulted in heavy losses for invaders.