The great city thus founded by William Penn is built chiefly upon a broad plain between the Delaware and Schuylkill Rivers, about one hundred miles from the sea, and upon the undulating surface to the north and west. The shape of the city is much like an hour-glass, between the rivers, although it spreads far west of the Schuylkill. The Delaware River, in front of the built-up portion, sweeps around a grand curve from northeast to south, and then, reversing the movement, flows around the Horseshoe Bend below the city, from south to west, to meet the Schuylkill. The railway and commercial facilities, the proximity to the coal-fields, and the ample room to spread in all directions, added to the cheapness of living, have made Philadelphia the greatest manufacturing city in the world, and attracted to it 1,300,000 inhabitants. The alluvial character of the shores of the two rivers surrounds the city with a region of the richest market gardens, and the adjoining counties are a wealthy agricultural and dairy section. Clay, underlying a large part of the surface, has furnished the bricks to build much of the town. Most of the people own their homes; there are over two hundred and fifty thousand dwellings and a thousand miles of paved streets, and new houses are put up by the thousands every year as additional territory is absorbed. When Penn laid out his town-plan, he made two broad highways pointing towards the cardinal points of the compass and crossing at right angles in the centre, where he located a public square of ten acres. The east and west street, one hundred feet wide, he placed at the narrowest part of the hour-glass, where the rivers approached within two miles of each other. This he called the High Street, but the public persisted in calling it Market Street. The north and south street, laid out in the centre of the plat, at its southern end reached the Delaware near the confluence with the Schuylkill. This street is one hundred and thirteen feet wide, Broad Street, a magnificent thoroughfare stretching for miles and bordered with handsome buildings. Upon the Centre Square was built a Quaker meeting-house, the Friends, while yet occupying the caves on the bluff banks of the Delaware that were their earliest dwellings, showing anxiety to maintain their forms of religious worship. This meeting-house has since multiplied into scores in the city and adjacent districts; for the sect, while not increasing in numbers, holds its own in wealth and importance, and has great influence in modern Philadelphia. Afterwards the Centre Square was used for the city water-works, and finally it was made the site of the City Hall.