Radar

The first one that used radios waves to detect was a German scientist, that show that he could find metal (a ship) in a fog, this happen in 1904, but he couldn’t not say how far away it was. The idea to find ship was a great idea and the USA, British, German, France and Japan all investigated in this technology. The first that make radar that was functional was the British, and they used it as defends against aircraft attack. The Germen though that these masts was death ray.