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.
Panama Canal
In 1921, Colombia and the United States entered into the Thomson–Urrutia Treaty, in which the United States agreed to pay Colombia $25 million: $5 million upon ratification, and four-$5 million annual payments, and grant Colombia special privileges in the Canal Zone. In return, Colombia recognized Panama as an independent nation.