A missile submarine is a type of military submarine designed to carry and launch ballistic missiles. These submarines are often equipped with advanced stealth technology, allowing them to operate undetected underwater. They play a crucial role in a nation's nuclear deterrent strategy, providing a second-strike capability in case of a nuclear attack. Typically, missile submarines are part of a country's naval fleet and can be classified as either nuclear-powered or diesel-electric. The most well-known missile submarines are the U.S. Navy's Ohio-class and the Russian Navy's Borei-class, both capable of launching long-range missiles from underwater.