THE SECRET WORLD OF SUBMARINES – HOW THEY SURVIVE DEEP BELOW | An explainer on how modern submarines operate, survive, and support their crew during long months underwater. This is an old story retold about the hidden world beneath the waves — the world of modern submarines. Nuclear-powered submarines are among the most complex machines ever built, engineered to travel thousands of miles without surfacing and designed for missions that remain unseen. A submarine’s nuclear reactor gives it virtua