Explanation: The Nile in Egypt was the center of Egyptian civilization, and is a remarkably stable river in most matters.

The Yellow River in China, likewise, was central in the foundation of Chinese civilization. It, however, is most certainly not a stable or predictable river, having numerous instances in Chinese history where its tempestuous behavior endangered or even toppled dynasties - or any number of times the Yellow River just straight-up decided to change course because it fucking felt like it.