SHANGHAI (AP) — A luxury hotel opening outside Shanghai is offering guests with deep pockets the chance of a very deep sleep.

The 18-story Intercontinental Shanghai Wonderland Hotel has been built into the side of a huge hole in the ground left by a former pit mine. Sixteen of its floors are below ground level, looking out onto the rest of the former quarry. Two floors are underwater.

“I designed many different types of buildings in U.K., in Europe, in Dubai, and so on but this one was totally different and became almost life work, so that’s why I’m saying it’s probably the most important building that I have designed,” said chief architect Martin Jochman, who is known for the sail-shaped Burj Al-Arab skyscraper in Dubai.

The project began in 2006 and construction got underway in 2013. The team faced delays and a host of technical challenges, including meeting strict earthquake regulations and maintaining water levels.

UNESCO representative Michael Croft described the 336-room hotel as a model for sustainable development.

“It’s a model that has been inspired by a vision of a better future, and a present that looks to its past for answers,” he said at a news conference introducing the hotel Thursday.

The hotel, which is in Songjiang near Shanghai Hongqiao International Airport, opens Tuesday. Rooms are priced from 3,666 to 6,000 yuan ($530 to $860).

“We could have abandoned this quarry,” said Xu Shitan, vice chairman of Hong Kong property developer Shimao Group, which developed the hotel. “But we didn’t. We turned it into a treasure.”