The HZMB is a 55-km (34 mi) bridge–tunnel system consisting of a series of 3 cable-stayed bridges, an undersea tunnel, and 4 artificial islands. It's both the longest sea crossing and the longest open-sea fixed link in the world. The HZMB spans the Lingding and Jiuzhou channels, connecting Hong Kong and Macau with Zhuhai.
The HZM Bridge was designed to last for 120 years and cost ¥127 billion (US$18.8 billion) to build.
The structure was completed on 2/6/2018 and journalists were taken for a ride over the bridge. On 10/24/2018, the HZMB was opened to the public after its inauguration a day earlier by Xi Jinping.