Short answers, pulled from the story.
The earliest evidence of hydropower dates back to the 4th century BC when water wheels began to appear in the ancient Near East. These early devices transformed how societies processed grain and operated machinery. The technology evolved from simple mechanical devices to complex electrical generators over thousands of years.
The French engineer Benoît Fourneyron developed the first hydropower turbine in the 19th century. This turbine was implemented in the commercial plant of Niagara Falls in 1895 and is still operating today. The invention marked a significant turning point in human history by converting rotary motion into usable power.
The Three Gorges Dam in China has an installed capacity of nearly 22,500 megawatts. The facility required the relocation of over 1.3 million people during its construction. It stands as the world's largest power station and serves as a geopolitical tool that has reshaped lives along the Yangtze River.
Between 1977 and 1990 the dam's turbines generated one third of Egypt's electricity. The project was funded by the Soviet Union after American and British funding was withdrawn. The dam triggered a dispute between Sudan and Egypt over the sharing of the Nile River.
Ethiopia began construction on the Grand Ethiopian Renaissance Dam in 2011. The project followed a 17-year-long Ethiopian Civil War and a coup d'état in 1974. Ethiopia took advantage of Cold War tensions to request assistance from the United States for irrigation and hydropower investments in the 1960s.
The first commercial hydroelectric plant in Italy was completed in 1898. This event signaled the end of the mechanical reign of 12,000 watermills that were churning in the 1890s. The new large plants moved power away from rural mountainous areas to urban centers in the lower plain.