Submarines are complex and expensive pieces of military hardware. The newest Virginia-class fast-attack submarines built for the US Navy cost around $4 billion each. For this price, they provide a powerful and versatile underwater capability.

Life inside one of these high-tech vessels is unique. Submarines are cramped, with little privacy or personal space. The crew areas are efficiently designed, with bunks, lockers and desks tucked into every corner. The submarine’s galley provides basic but essential food to feed over 130 sailors during months-long deployments.

Operating a submarine is intense teamwork, with each crew member playing a critical role. Sailors standing watch track sonar contacts, maintain the nuclear reactor, monitor atmosphere quality, and operate a dizzying array of systems. Coordination and discipline keep the boat running safely. Drills are constantly practiced to ensure the crew reacts correctly in emergencies.

The payoff for this challenging duty is getting to operate an extremely capable underwater warship. Virginia-class submarines are fast, stealthy and heavily-armed with torpedoes and missiles. They gather intelligence, deploy special forces, and if needed, destroy enemy ships and submarines. Their nuclear reactor grants the ability to remain submerged for months, able to surface on the other side of the world.

Life on a submarine isn’t easy or comfortable. But the privilege of operating these complex machines and serving in an elite community makes it rewarding. The sailors assigned to $4 billion submarines form close bonds while carrying out difficult but essential missions beneath the waves.

VIDEO: