In Chinese history, the capital (首都 - shǒudū) was more than just a political center; it was the cosmic center of the “Middle Kingdom” (中国 - Zhōngguó), the place where the Emperor, the “Son of Heaven,” resided. The location and fortune of the capital were deeply tied to the “Mandate of Heaven” (天命 - tiānmìng), the divine justification for a dynasty's rule. Therefore, a `故都` is a powerful symbol. It represents a fallen dynasty, a bygone era, and the cyclical nature of power. Visiting a `故都` is often a sentimental journey, an act of `怀古` (huáigǔ) - cherishing and reflecting on the past.
Comparison to a Western Concept: In the West, we might talk about “the former capital,” like Philadelphia in the U.S., or historical centers of power like Rome. However, there isn't a single, common word like `故都` that carries the same weight. The closest feeling might be how people refer to “Ancient Rome” or “Ancient Athens”—places that were once the heart of vast empires and are now revered historical treasures. The key difference is that `故都` is a general term that can be applied to *any* of China's many former capitals (Xi'an, Luoyang, Kaifeng, Nanjing, etc.), each one a chapter in the nation's long story.