25 April 1960 – First submerged circumnavigation of the Earth was completed by a Triton submarine.

Operation Sandblast was the code name for the first submerged circumnavigation of the world executed by the United States Navy nuclear-powered radar picket submarine USS Triton (SSRN-586) in 1960 while under the command of Captain Edward L. Beach, USN.

The New York Times described Triton ’​s submerged circumnavigation of the Earth as “a triumph of human prowess and engineering skill, a feat which the United States Navy can rank as one of its bright victories in man’s ultimate conquest of the seas.” The actual circumnavigation took place between 24 February and 25 April 1960, covering 26,723 nautical miles over 60 days and 21 hours. Operation Sandblast used the St. Peter and Paul Rocks, located in the middle of the Atlantic Ocean near the Equator, as the starting point and terminus for the circumnavigation.

During the course of the circumnavigation, Triton crossed the Equator four times while maintaining an average speed of advance (SOA) of 18 knots. Triton ’​s overall navigational track during Operation Sandblast generally followed the same course for the first circumnavigation of the world led by Portuguese explorer Ferdinand Magellan between 1519-1522.