The US is understood to have started developing "underwater drones" amid a potential threat of war with China. A secretive ...

However, post-war flags sometimes depict the silhouette of a ship instead. Symbols of mines indicated mine-laying operations, while other operations, such as when a submarine was used as a ...

The first time the world caught a glimpse of the latest prototype submarine, it was an eagle-eyed Google Maps user who spotted the secretive underwater drone. Satellite images showed Northrop ...