China has finally opened the 50km-long Shenzhen-Zhongshan Link to traffic.

This bridge-tunnel system spans two sides of the Pearl River Delta near Hong Kong.

Construction on the project began in 2017 to connect the city of Zhongshan to Shenzhen.

It consists of a 6.7km tunnel starting on the Shenzhen side leading to 19 bridges, totalling 43km in length. The tunnel is the world’s longest and widest underwater steel-shell concrete tunnel and is equipped with numerous devices to ensure its safe and stable operation. This includes 14 robots, dual-wavelength flame detectors and Beidou satellite navigation signal simulators.

Traffic can be rerouted in the event of a car accident with built-in loudspeakers, while an extensive array of cameras will convey any incidents to a remote-control centre in real time. Other technologies employed include a horizontal smoke exhaust pipe system in the event of a fire that also allows for safe evacuations across interchangeable undersea tunnels.

The tunnel,...