China inaugurated the country's largest underwater road tunnel this week, which immediately became open to vehicle traffic. Construction of the infrastructure took four years - as of January 9, 2018 - and is 10.79 kilometers (6.65 miles) long.

The Taihu Tunnel extends under Taihu Lake in East China's Jiangsu Province, about 50 kilometers east of Shanghai.

According to government officials in Jiangsu, the tunnel was built at a cost of about $1.56 billion.

More than two million cubic meters of concrete were used to build the two-way tunnel, which has six lanes and is 17.45 meters wide, according to the news agency, Xinhua.

The tunnel roof has been equipped with LED colored lights, designed to prevent driver fatigue.

The tunnel is part of the 43.9-kilometer Changzhou-Wuxi highway, which opened to the public on December 30, 2021. It provides an alternative expressway for commuters between Shanghai and Nanjing, the capital of Jiangsu.

Connecting the Suzhou, Wuxi and Changzhou expressways, it was built to relieve traffic pressure on cities near Taihu Lake while promoting the economic development of cities in the Yangtze River Delta area.