Construction of the long-awaited Hong Kong-Zhuhai-Macao Bridge took a big step toward completion on Tuesday when workers began to install the final piece of an underwater tunnel.

The final joint of the last 5.6-kilometer section was lowered into the Lingding Channel, the central channel of the Pearl River, in ideal weather conditions, according to Wang Zhanggui, chief engineer at the National Marine Environmental Forecasting Center.

Completion of the tunnel will effectively end work on the road link between Hong Kong, Macao and Zhuhai, Guangdong province. It is scheduled to open to traffic this year.