The world's longest bridge is the Danyang–Kunshan Grand Bridge in China, part of the Beijing-Shanghai High-Speed Railway. The bridge, which opened in June 2011, spans 102.4 miles (165 kilometers). Another part of that train line, the 70.8-mile (114-km) long Langfang–Qingxian viaduct, is the second longest bridge in the world.
China constructed the Danyang–Kunshan Grand Bridge in just 4 years, employing 10,000 workers, at a cost of about $8.5 million. It crosses low rice paddies, part of the Yangtze River Delta, with just a few miles of the bridge actually crossing the open water of Yangcheng Lake in Suzhou. The bridge averages about 100 feet (31 meters) off the ground.
The world's longest road bridge is the 34-mile (55-km) long Bang Na expressway in Thailand, a six-lane elevated highway that crosses only a bit of water, the Bang Pakong River. Constructing the massive bridge required more than 1,800,000 cubic meters of concrete.
The world's longest continuous bridge over water is the Lake Pontchartrain Causeway in southern Louisiana. The causeway is actually two parallel bridges, with the longer of the two measuring 23.83 miles (38 km). The bridges are supported by 9,500 concrete pilings.
Louisiana's famous bridge faced a challenger in 2011, when China claimed that its Jiaozhou Bay Bridge was the longest spanning water. Guinness World Records decided to split the title into two parts, stating that the 26.4-mile (42.5-km) long Jiaozhou Bay Bridge is the longest bridge over water in aggregate, while the Pontchartrain is the longest continuous bridge. In Jiaozhou, land bridges and sea tunnels make up parts of the overall structure.