China has opened the world's longest cross-sea bridge.
The Jiaozhou Bay bridge is 42km long and links China's eastern port city of Qingdao to an offshore island, Huangdao.
State-run CCTV says the 35m-wide bridge is the longest of its kind and cost more than 10 billion yuan ($A1.41 billion).
CCTV says the bridge passed construction appraisals on Monday and the bridge and an undersea tunnel opened to traffic yesterday.
It has taken four years to build the bridge, which is supported by more than 5,000 pillars.
According to Guinness World Records, the previous record holder for a bridge over water is the Lake Pontchartrain Causeway in Louisiana.
Two groups of workers have been building it from different ends of the structure since 2006.
Another Chinese bridge will beat that record in the next few years. Construction has started on a bridge to link southern Guangdong province with Hong Kong and Macau and both bridges will be dwarfed by the longest bridge in the world, also in China.
The Danyang-Kunshan Grand Bridge will be 164km long.