China has announced construction of the world's longest sea bridge — barely 18 months after opening the current record-holder, reports The Guardian.

The bridge will connect Hong Kong and Macau with China and will span a whopping 50 kilometers, surpassing the longest sea bridge currently by 12 kilometer. Once completed, it will cut driving time from Hong Kong to Zhuhai from four hours to one.

An engineering marvel in its own right, the bridge design will also include a 5.5 kilometer underwater tunnel with artificial islands to join it to bridges on each side. That will make it the first major marine bridge-and-tunnel project ever attempted in China, and the underwater tube will also be the longest of its kind in the world.

The bridge will be built to withstand winds over 200 kmph, resist the rumbling of a magnitude 8 earthquake, and absorb the impact of a 300,000 ton ship. Furthermore, by fusing the expanse between Hong Kong and Macau, planners hope to transform the area into one of the world's most vibrant economic centers by 2020.

But a project as massive as this comes with its share of criticism. The World Wildlife Fund and other environmental groups are warning that construction will devastate the estuary of the Pearl River and endanger the rare Chinese white dolphin. There are also concerns about how the bridge will affect the flow of water in the area, altering an ecosystem that hangs in a careful balance.

"We will control the construction noises and turbidity of seawater, and prevent oil pollution," reassured Zhu Yongling, an official in charge of the project construction. Also, designers have limited the size and number of columns in the water to minimize their impact on estuary flows.

All in all, the project will cost of 73 billion yuan (about $10.6 billion,) and is due to be completed by 2015.