Workers celebrate the completion of the tunnel beneath Taihu Lake on Jan 6. [Photo/Suzhou Daily]

When construction work on a tunnel running beneath Taihu Lake, in the city of Suzhou, Jiangsu province, was completed the morning of Jan 6, it marked a historical event as the first tunnel under the lake and the longest distance between any two of the city's Metro stations.

The tunnel itself is 730 meters long, and the distance between the Huagang Rd Station and Jiangling West Rd Station on Metro Line 4, is 2,786 meters.