Introduction to the Nanjing City Wall: The terrain of Stone City is steep and it has been known as the "Tiger in Stone City" since ancient times. After Zhu Yuanzhang established Nanjing as his capital in the Ming Dynasty, he built the city wall in the second year of Hongwu. The stone city here became part of the Nanjing city wall. Nowadays, Stone City is a famous historical monument at home and abroad and one of the important tourist attractions in Nanjing.