Modern concrete was invented in 1824 by Joseph Aspdin. Although concrete was used in ancient times by the Egyptians and Romans, who used gypsum and lime for mortar, cement-making techniques were later lost for many years. By the end of the 19th century, America had built its first concrete bridge (the Alvord Lake Bridge in San Francisco, California) and its first concrete street (in Bellefontaine, Ohio, and it is still around today). In 1904, the first concrete skyscraper was built in Cincinnati, Ohio. Read more