How Underground Fiber Optics Spy on Humans Moving Above
Vibrations from cars and pedestrians create unique signals in cables. Now scientists have used the trick to show how Covid-19 brought life to a halt.
▻https://www.wired.com/story/how-underground-fiber-optics-spy-on-humans-moving-above/#intcid=recommendations_right-rail-personalized-popularity-experiment_edce193