Chinese engineers are testing techniques that could be used to build a 1,000km tunnel – the world’s longest – to carry water from Tibet to Xinjiang, the South China Morning Post reports. The proposed tunnel, which would drop down from the world’s highest plateau in multiple sections connected by waterfalls, would “turn Xinjiang into California,” one geotechnical engineer said. China’s longest tunnel is the eight-year-old 85km Dahuofang water project in Liaoning province, while the world’s longest tunnel is the 137km main water supply pipe beneath the city of New York. However, the Chinese government started building a tunnel in the center of Yunnan province in August that will be more than 600km long, local media reported. Comprising more than 60 sections, each wide enough to accommodate two high-speed trains, it will pass through mountains several thousand meters above sea level in an area plagued by unstable geological conditions. Researchers said building the Yunnan tunnel would be a “rehearsal” of the new technology.