Panama Canal
Colombia, France, and later the United States controlled the territory surrounding the canal during construction. The US continued to control the canal and surrounding Panama Canal Zone until the 1977 Torrijos–Carter Treaties provided for handover to Panama. After a period of joint American–Panamanian control, in 1999, the canal was taken over by the Panamanian government. It is now managed and operated by the government-owned Panama Canal Authority.
Separation of Panama from Colombia
In 1903, the United States and Colombia signed the Hay–Herrán Treaty to finalize the construction of the Panama Canal but the process was not completed because the Congress of Colombia rejected the measure (which the Colombian government had proposed) on August 12, 1903. The United States then moved to support the separatist movement in Panama to gain control over the remnants of the French attempt at building a canal.