The sixth immersed tube of a 6.8-km-long undersea immersed tube tunnel in south China's Guangdong Province was installed on Wednesday. So far, 948.5 meters of the immersed tube tunnel has been built. The tunnel, which is made up of 32 tubes, forms part of the Shenzhen-Zhongshan cross-sea link project. The 24-kilometer link connecting the cities of Shenzhen and Zhongshan will play an important role in development of the Guangdong-Hong Kong-Macao Greater Bay Area. The link includes the 6.8-kilometer underwater tunnel and two artificial islands. The tunnel is the world's first undersea immersed tube tunnel with four lanes in each direction. The Shenzhen-Zhongshan cross-sea link will open to traffic in 2024. It will cut travel time between the two cities from two hours to 30 minutes.