The Hong Kong-Zhuhai-Macau Bridge runs 34 miles (55 kilometers) across the Pearl River estuary. It links Hong Kong, Zhuhai and Macau.
It is the longest sea crossing and the longest permanent road link in open sea.
Work started on December 15, 2009. It opened on October 24, 2018.
Halfway across, cars do not stay on the bridge.
They enter a 4.2-mile tunnel between two artificial islands. Ships pass overhead.
The sunken tunnel was not bored through rock.
It was assembled from hollow sections, lowered and joined under the water.
The islands at its ends are artificial.
There the road leaves the bridge and goes under the sea.
One standard segment weighs 80,000 tons.
Hydraulic jacks, rams pushed by fluid under pressure, had to shove each one into place.
How heavy is a piece like that?
As heavy as more than 13,000 African elephants piled on the seabed.
Before this, the trip went by ferry and took hours.
The link is built to last 120 years against typhoons, earthquakes and a ship strike.
From above it looks like one long bridge.
Underneath, concrete holds the sea back.
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