Philadelphia

The City Plan of Philadelphia is a seminal creation in American city planning in that it was the first American City Plan to provide open public squares for the free enjoyment of the community and a gridiron street pattern featuring streets of varying widths: wide main streets and narrower side streets. In addition this plan was the first city plan in the United States to provide for long-term urban growth. These features inspired the planners of many cities to adopt the Philadelphia Plan as a model. 

After an initial difficulty in attracting customers (who were used to getting their water from public pumps and private wells and cisterns), Philadelphia's waterworks soon couldn't keep up with demand. John Davis and Frederick Graff designed a complete remodeling of the system in 1811 so that it could supply the city's growing needs. 

Philadelphia City Hall was the largest masonry load-bearing wall building in the world at the time of its completion in 1901, stood as the tallest occupied building in the United States until 1909, and still is the largest city hall in the United States. The building covers 14.26 acres, originally contained 634 rooms with over 1 million square feet of space, and with its tower and statue of William Penn rises a total of 548 feet above the ground. The construction of Philadelphia City Hall began in 1872 and was completed in 1901.

In 1751 Benjamin Franklin published “Experiments and Observations on Electricity, Made at Philadelphia in America.” Experiments summarized in this booklet determined the existence of positive and negative charges, and the difference between insulators and conductors. This work led to the invention of the lightning rod. Its complete construction was popularized in Poor Richard’s Almanack in 1753. This is the first practical engineering application of electricity. A unifying theory covering static electricity, lightning, and stored charge was invented.