Give one's life for a just cause
China has a history of producing lime for at least 1000 years. Yu Qian, an outstanding politician and strategist in the Ming Dynasty, once wrote a poem "Ode to Lime": "Beat mountains with a thousand hammers, and nothing will burn when you are idle. I am not afraid of broken bones, I want to stay innocent in the world. " He praised the fine quality and unyielding spirit of lime with anthropomorphic creative techniques. As can be seen from Qian's poems, in the Ming Dynasty, our people had mastered the technology of burning lime with limestone. Xu Xiake, an outstanding traveler and geographer in the late Ming Dynasty, traveled all over China. In his masterpiece Xu Xiake's Travels, he first revealed the limestone landform in southwest China, which was more than 0/00 years before Europeans discovered limestone.