A top-secret US submarine drone weapon dubbed the 'Manta Ray' has been spotted by hawk-eyed online users on Google Earth - and remains visible to the public. The vessel - named after the sea creature due to its diamond-shaped body and wing-like fins - is used for underwater threat detection and was designed by Northrop Grumman Corporation. 🎥 Google Earth #mantaray #topsecret #drone #navy #usnavy