上面照片是美国杰弗逊国家纪念碑,又叫做杰弗逊纪念拱门,它位于美国中部密西西比河中游最大的港口城市——密苏里州圣路易斯市,建于20世纪60年代,是由当代著名建筑师小沙里宁设计.纪念碑是为纪念美国先辈移民开拓西部而建筑,它是一条抛物线形的拱门,这条抛物线的高和宽都为190米,游人可以乘电梯直达拱顶观光. The photo above is the Jefferson National Memorial, also known as the Jefferson Memorial Arch. It is located in St. Louis, Missouri, the largest port city in the middle of the Mississippi River in the United States. Built in the 1960s, it was designed by the famous contemporary architect, Sarinaing. The monument was built to commemorate the immigration of American ancestors into the west. It is a parabolic arch. The height and width of this parabola are all 190 meters. Visitors can take the elevator to the vault.