Masonry

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.

Inferior water and the lack of a sufficient water supply prompted public pressure to find a significant water source for the 360,000 of people living in New York City at the time. Studies determined that the Croton River, 40 miles north of the city, was the best available source. The original system served as a prototype for large-scale water supply projects across America. 

For more than 174 years, the Canton Viaduct has stood as a dominating structure on the New England landscape. When completed in 1835, the slightly curved, granite masonry bridge - 615 feet long, 70 feet high, and 22 feet wide - carried a single track of the Boston and Providence Railroad, providing a critical link in the establishment of rail service between Boston and New York. In 1860, a second track was added. With few major alterations, the viaduct has continued to provide safe rail transportation to heavier and faster loads throughout the 20th century.