One of the proudest moments in state history occurred 60 years ago Tuesday, when the USS Nautilus, the world's first nuclear-powered submarine, slid into the Thames River at Groton. The christening, by first lady Mamie Eisenhower, on Jan. 21, 1954, heralded a new era of naval history.

Leading the country in submarine technology is nothing new for Connecticut. David Bushnell's Turtle, built in Old Saybrook in 1775, was the first underwater craft used in combat. Electric Boat Co. of Groton, now a division of General Dynamics, had sold the Navy its first submarine in 1900.

During World War II, EB built 74 submarines. The Nautilus, however, cemented the Groton-New London area's role as submarine capital of the world.

The switch from diesel to nuclear power brought several advantages. It gave submersible craft a virtually unlimited range. Because nuclear propulsion needs no oxygen, submarines can stay under water for weeks. They can also escape detection by radar.

"Underway on nuclear power" was the historic message radioed from the Nautilus when she finally put to sea a year after the christening, following more construction and testing. She then headed for Puerto Rico, traveling the entire 1,300 miles under water — a submarine distance record for the time.

But her finest moment was yet to come. On Aug. 3, 1958, the Nautilus passed directly under the North Pole, the first watercraft to do so. The trip was hazardous not only because of the thick polar ice but because at that location normal compasses don't work.

The polar crossing scored Cold War points for the United States, too. Ten months earlier, the Soviet Union had launched Sputnik I, the world's first artificial satellite. Now America could claim a record-breaking technological feat of its own.

Decommissioned in 1980, the Nautilus now rests at her birthplace, a museum open to the public, a symbol of the time the United States — and specifically Connecticut — led the way beneath the waves.

As they continue to do.