History of the Panama Canal
During World War II, the canal proved a vital part of the U.S. military strategy, allowing ships to transfer easily between the Atlantic and Pacific. Politically, the Canal remained a territory of the United States until 1977, when the Torrijos–Carter Treaties began the process of transferring territorial control of the Panama Canal Zone to Panama, a process completed on 31 December 1999.
Palmyra Atoll
With imminent opening of the Panama Canal, Palmyra became strategically important. Britain had established a submarine cable station for the All Red Line on nearby Fanning Island. So the U.S. Navy sent to Palmyra, where on February 21, 1912, American sovereignty was formally reaffirmed.