Here's what life is like aboard the largest US Navy submarine
Submarines are a tremendous strategic and tactical advantage to countries that have them.
They range from small attack submarines used for naval and anti-submarine warfare to large ballistic-style submarines armed with nuclear weapons that could wipe out entire nations.
Launched in 1988, the Ohio-class USS Pennsylvania (SSBN-735) is currently the largest vessel in the U.S. Navy's arsenal. It is 560-feet long and berths 165 sailors, according to the National Geographic video below.
This video shows the ship's incredible fire power, tactics and what life is like for the crew that man it.