海市蜃楼

Explanation: Mirage: large clams. Originally referred to the sea or the desert, due to the reverse and refraction of light, air or ground tower castle appears illusory. Metaphor is nothing more than Piaomiao things. 　　Usage: Joint type; as subject, object, attribute; containing derogatory 　　Source: Qian Han, "Historical Records Official Book": "Waterfront mirage weather tower, Hirono natural gas into the palace." 　　Examples: Fifth Dharma with a disciple out of the river is returned, and play a ~, bustling. (Qing Cao Xueqin's "Dream of Red Mansions," the eighty-fifth back) 　　Results: Great Gobi make faces 　　Postscript: Great Gobi make faces 　　Riddle: A city on the Pacific Thesaurus:  absurd and unreasonable, fictitious zilch, castle in the air; daydream; ivory tower, a mare's nest, like a dream and a bubble's shadow, Mirage sea City, Ivory tower