1960: The USS Triton, a nuclear-powered radar picket submarine, arrives in Groton, Connecticut, after completing the first completely submerged circumnavigation of Earth. It spends 60 days, 21 hours under water.

The Triton put to sea Feb. 15, and the crew was told to prepare to stay out longer than normal. Still submerged, the boat reached St. Peter and St. Paul Rocks in the mid-Atlantic east of Brazil on Feb. 24, where the men on board were informed of the Navy’s plans.

In the following weeks, Triton rounded Cape Horn, crossed the Pacific and Indian oceans, then slipped past the Cape of Good...