The Taihu tunnel, China’s longest underwater highway tunnel, opened to traffic in east China’s Jiangsu Province.

The 10.79-kilometer-long, 7.25-meter-tall tunnel runs under Taihu Lake, China’s third-largest freshwater lake.

It is part of the 43.9-kilometer Changzhou-Wuxi Highway, which also opened to traffic on Thursday.

Construction of the underwater tunnel began in January 2018.

The project utilized automatic steel processing equipment and intelligent systems that could ensure zero discharge of sewage.

The underwater tunnel portion of the Tokyo Bay Aqua-Line, a vehicle highway that travels under Tokyo Bay, is 9.6 kilometers. 

In terms of underwater tunnels in general, though, the top honor goes to the Channel Tunnel, which connects England and France by rail.

Its submerged portion runs for 37.9 kilometers, the longest of any underwater tunnel in the world.