Exact location, unknown. Size, off the charts. That's a newly built radio antenna in China that could have military applications but comes with possible health risks, CBS News reports. The Wireless Electromagnetic Method project was built over 13 years on a huge tract of land—1,400 square miles, or nearly five times the space filled by New York City—and officially exists to spot minerals and earthquakes. But the South China Morning Post says its extremely low-frequency radio waves can also reach deep-sea submarines, lowering their risk of having to come up to receive messages.
The project follows China's first station for so-called ELF waves in 2009; a year later, China communicated with one of its nuclear subs in deep water, making it the world's third nation to have such submarine transmissions (along with the US and Russia). But the World Health Organization warns that even short-term exposure to these waves at high levels can affect human nerves and muscles and alter the central nervous system. WHO recommended creating exposure guidelines and doing further study, while a researcher in Beijing asked his nation's Ministry of Ecology and Environment to review the tower's environmental effects. That request was rejected. (China has also built a stunning 34-mile bridge.)