THE greatest cataract in the world is the Falls of Niagara, where the waters, accumulated from the great upper lakes, forming a river three-quarters of a mile in width, are suddenly contracted and plunged over the rocks in two columns, to the depth of one hundred and sixty feet. The greatest cave in the world is the Mammoth Cave in Kentucky, where one can make a voyage on the waves of a subterranean river, and catch fish without eyes. The greatest river in the world is the Mississippi, four thousand one hundred miles in length. Its name is derived from an Indian word meaning "the Father of Waters." The largest valley in the world is the valley of the Mississippi. It contains five hundred thousand square miles, and is one of the most prolific regions on the globe. The largest lake in the world is Lake Superior, four hundred and thirty miles long. The greatest natural bridge in the world is that over Cedar Creek, in Virginia. It extends over a chasm of eighty feet in width, and two hundred and fifty feet deep, at the bottom of which a creek flows. The greatest solid mass of iron in the world is the iron mountain of Missouri. It is three hundred and fifty feet high, and two miles in circuit. The longest railroad in the world is the Central Railroad of Illinois, which is seven hundred and thirty-one miles long—and cost fifteen millions of dollars. The greatest number of miles of railroad, in proportion to its surface, of any country in the world, is in Massachusetts, which has over one mile to every square mile of its area. The greatest number of clocks manufactured in the world, is turned out by the small State of Connecticut. The largest number of whaleships in the world are sent out by Nantucket and New Bedford. The greatest grain port in the world is Chicago. The largest aqueduct in the world is the Croton aqueduct in New York. It is forty and a half miles long, and cost twelve and a half millions of dollars.