1999 - Panama Canal
The Isthmus of Panama was the perfect place for a canal connecting the Pacific and Atlantic Oceans. The French tried to build one in the late 19th century, but the effort was taken over by the United States in 1904. Opened in 1914, the United States controled the Canal Zone in return for helping Panama acheive their independence. However by the 1970's, Panama wanted control of its land returned so the Torrijos-Carter Treaty of 1977 set out a timeline for transfering ownership. On December 31, 1999, the management of the canal was turned over to the Panama Canal Authority.