query: What is the longest canal in the world?
passage: Grand Canal (China)
The Grand Canal, known to the Chinese as the Beijing–Hangzhou Grand Canal (Jīng-Háng Dà Yùnhé), a UNESCO World Heritage Site, is the longest as well as the oldest canal or artificial river in the world.[1] Starting at Beijing, it passes through Tianjin and the provinces of Hebei, Shandong, Jiangsu and Zhejiang to the city of Hangzhou, linking the Yellow River and Yangtze River. The oldest parts of the canal date back to the 5th century BC, but the various sections were first connected during the Sui dynasty (581–618 AD). Dynasties in 1271-1633 significantly rebuilt the canal and altered its route to supply their capital Beijing.
passage: Dahuofang Water Tunnel
The Dahuofang Water Tunnel (Chinese: ), located in Liaoning Province, China is an tunnel eight meters in diameter which provides water from the Dahuofang Reservoir to the cities of Shenyang, Fushun, Liaoyang, Anshan, Panjin, Yingkou, and Dalian. , it is the third longest tunnel in the world. Boring of the tunnel began in September 2006, was completed in April 2009, and cost 5.2 billion yuan (about $750 million).