Shimao Wonderland InterContinental Quarry Hotel resembles a waterfall tumbling over a cliff. [Photo provided to chinadaily.com.cn]

The long-awaited underground hotel being built in Shanghai's Sheshan National Tourist Resort is one step closer to completion with trial operation expected to take place in early 2018.

Shimao Wonderland InterContinental Quarry Hotel is a uniquely designed project in which the hotel is burrowed into the walls of an 80-meter-deep former quarry.

Shimao Group first announced it planned to build a five-star hotel on the site in 2006. But it took until 2013 to solve several technical problems involved in such a complex architectural project.

The hotel will consist of over 400 guest rooms and 18 floors, only two of which are above ground. The bottom two floors are not only underground, but underwater too, with guests able to look out directly into the depths of the lake. The underground hotel is expected to open next year. In addition to guest rooms, the hotel also provides a luxurious underwater restaurant and recreation projects including cliff abseiling and suspended walkways.