For thousands of years, mankind has engineered remarkable structures such as the pyramids of Egypt and the Great Wall of China. More recently, visionary engineers have undertaken massive transportation and communications projects that have pushed the boundaries of human ingenuity. Here is a roundup of 10 engineering marvels that changed world history. 1. Panama Canal A shovel vehicle operates during the construction of the Panama Canal, c. 1906. Hulton Archive/Getty Images Linking the Atlantic and Pacific Oceans, the 51-mile Panama Canal transformed global trade routes when it opened in 1914. After a failed attempt by the French in the 1880s, the United States re-started construction in 1904. Chief engineer John…