What right did the U.S. retain when it gave Panama Canal away?

The United States did not give the Panama Canal away. The canal and the surrounding Panama Canal Zone were under the control of the U.S. from 1903 until 1979, when they were transferred to Panama under the terms of the Panama Canal Treaty. The U.S. did retain certain rights under the treaty, including the right to defend the canal and the right to use it for military purposes.