But make no mistake: they are churning cauldrons of violence, barely constrained thermonuclear generators, creating enough energy to vaporize the Earth a thousand times over.
This class consists of four cruise missile submarines and 14 ballistic missile submarines which carry almost half of America's active strategic thermonuclear warheads.
Not all thermonuclear weapons yield as much power as Tsar Bomba, but even lesser bombs, like the United States B-41, can bring unimaginable destruction.
Thermonuclear weapons still use fission to generate heat and explosive power, but they also employ nuclear fusion, combining smaller hydrogen atoms under extremely high temperatures.