The United States Capitol is among the most symbolically important and architecturally impressive buildings in the nation. Construction of the original Capitol began in 1793, but it has been through several additions and alterations. Over its lifetime, the Capitol building has been built, burnt, rebuilt, extended, and restored.
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.
At a time when steam power was finding its first uses in America, Philadelphia opened two steam pumping stations, January 1801, to lift water from the Schuylkill River and distribute it through the city's wooden pipes and mains. By 1811 a new water power works was begun on the river near Morris Hill, and the Fairmount Water Works opened September 7, 1815. These water works represented the first large-scale application of steam pumping to water service in the country.
"The roundhouse is an amazing survivor of an important era in American engineering and architectural history. Eric DeLony, chief of the National Park Service's Historic American Engineering Record, has called it 'the most important surviving cast-iron framed building in North America.'"
From: The Baltimore and Ohio Railroad Martinsburg Shop Complex: Historic Structure Report. By John P. Hankey, August, 2000.