It's been said that even China's population of 1.4 billion couldn't fill all the empty homes. Many are high-rise apartments in gleaming new financial districts that initially failed to take off.

China’s long economic boom famously left it dotted with an overbuilt landscape of empty apartment towers and decrepit shopping malls. Tracking these “ghost cities” has become a fixation of economists ...

For years, physicists have been baffled by the discovery of mysterious “ghost particles”. But thanks to a new liquid dome in a futuristic underground observatory located in the hills of China, ...