The document summarizes the history and construction of two major infrastructure projects: 1) The Panama Canal, which took decades to complete and involved overcoming numerous engineering challenges, health issues like yellow fever, and changes in leadership between the French and American efforts. It opened in 1914 and remains a vital shipping route. 2) The Los Angeles Aqueduct, which was envisioned and led by engineer William Mulholland to provide a new water source for the growing city from the Owens River over 200 miles away. It involved extensive land purchases and took 5 years to build, transforming Los Angeles and the San Fernando Valley.