China opened the world's longest cross-sea bridge Thursday.

The 36-kilometer Jiaozhou Bay Bridge stretches from China's eastern port city of Qingdao to the island district of Huangdao.

Chinese media say the bridge – touted as the longest of its kind – cost more than $2.3 billion.

The official Xinhua news agency says the bridge will cut travel time from about 45 minutes to 20 minutes.

Authorities say the bridge is expected to boost development of an industrial zone in Huangdao and increase the port's capacity.

Separately Thursday, China launched its inaugural run of high-speed train service between Beijing and Shanghai. The bullet train will make the 1,300-kilometer trip in less than five hours at a price of around $85, less than half the plane fare.