The Sierra I submarine was one of the most advanced Soviet attack submarines of the Cold War. Built with a titanium hull, it could dive deeper than most submarines while remaining relatively quiet ...

Historic submarines are surprisingly similar to those deployed by today's Navy and can provide an unprecedented look into modern combat at sea.

Operating the world's largest navy by hull count, China possesses combat vessels—including surface warships and submarines—acquired from Russia decades ago, that helped it build sea power capable of ...