HEFEI, CHINA: On a leafy campus in eastern China, crews are working day and night to finish a mammoth round structure with two sweeping arms the length of aircraft carriers.
On former rice fields in the country’s southwest, a hulking, X-shaped building is being built with equal urgency under great secrecy. That facility’s existence wasn’t widely known until researchers spotted it in satellite images a year or so ago.
Together, the colossal projects are China’s most ambitious efforts yet to harness an energy source that could transform civilisation:…
