Recent archaeological evidence reveals early Virginia, which included both the Roanoke and Jamestown colonies, as the birthplace of the American chemical enterprise. Chemical processes first applied experimentally at Roanoke were re-introduced at Jamestown twenty years later.
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.
"For 273 years, the little stone bridge that carries Frankford Ave. across Pennypack Creek has been doing its humble job with a minimum of attention..."
- Gerald McKelvey, The Philadelphia Inquirer, September 16, 1970
The fort was constructed of coquina rock. Unique to Florida, the rock consists of millions of seashells cemented together. It proved highly durable and easily absorbed the force of many cannon balls.
The Castillo de San Marcos was the first permanent European settlement in the continental United States. Originally an outpost of the Spanish Empire, it is the oldest major engineered structure existing in America.
The Saugus Ironworks, the first commercial ironworks in North America, was an impressive technological achievement for an early colony. The same basic processes are used today: reducing iron oxide with carbon to produce metallic iron that can be cast in a mold, producing wrought iron by puddling cast iron, and fabricating wrought iron with power hammer and rolls.