The busy Hong Kong Cross Harbour Tunnel
The Cross-Harbour Tunnel (abbreviated CHT or XHT) is the first tunnel in Hong Kong built underwater. It is two steel road tunnels each with two lanes constructed using the single shell immersed tube method.
It is the earliest of three vehicular harbour crossings in Hong Kong, opened for traffic on 2 August 1972. It was constructed under 30-year private-sector franchise based on a build–operate–transfer model, and title passed to the Hong Kong government in August 1999 upon termination of the franchise. It has become one of the most congested roads (mainly towards the Hong Kong Island direction) in Hong Kong and the world. ( short from Wikipedia ).