2011年12月11日,西安安定门一侧的城墙裂缝栖满麻雀,成为冬日的鸟巢。西安城墙于明洪武年间在隋唐皇城基础上扩建保留至今,至今已有600多年历史,是中国现存规模最大、保存最完整的一座古代城垣建筑,具有重大历史和文物价值。但近几年先后出现墙基沉 December 11, 2011, Xi’an Andingmen side of the wall cracks perched sparrow, a winter nest. Xi’an city wall in the Ming Hongwu years in the Sui and Tang Dynasties built on the basis of the Imperial expansion has so far, has been more than 600 years of history, is China’s existing largest and most complete preservation of an ancient city wall architecture, has a significant historical and cultural value. But in recent years there has been wall-based sink