Senses
万里长城/ 萬里長城 Great Wall of China
The massive system of defensive walls in northern China, stretching from Shanhaiguan in the east to Jiayuguan in the west
万里长城/ 萬里長城 impregnable defense
Metaphor for a dependable national defense force or a person of great importance to the state's security, often used in the context of self-destruction