西安，古称长安，是著名的古都，也是中华文明的发祥地。它断断续续作为13个王朝的首都达1200多年之久。西安是中国古代第一个对外开放的城市。汉唐时期，它是中国政治、经济、文化和对外交流的中心。西安有很多珍贵的文物和遗址、秦始皇兵马俑，被誉为“世界第八大奇迹“。西安古城墙是世界上规模最大、保存最完整的古城墙遗址。灿烂的文化、悠久的历史以及丰富的文物和遗址，使得西安享有“自然史博物馆“的美称。

参考译文：

Xi'an, called Chang'an in ancient times, was an ancient capital and the birthplace of Chinese civilization. It served intermittently as the capital of 13 dynasties over 1,200 years. Xi’an was the first city to open its doors to the world in ancient China. In the Han and Tang Dynasties, it was the center of China's politics, economy, culture and international exchange. There are a large number of treasured cultural relics and sites in Xi'an. The Terra-cotta Warriors and Horses are honored as “The Eighth Wonder of the World“. The Ancient City Wall of Xi’an is the largest, best preserved ruin of ancient city wall in the world. Owing to its brilliant culture, long history, as well as abundant relics and sites, Xi'an enjoys the laudatory title of “Natural History Museum“.