United States territorial acquisitions
The Panama Canal Zone was an unorganized US territory located within the Republic of Panama. It was established under the Hay–Bunau-Varilla Treaty in 1903 and disestablished in 1979 under the Torrijos–Carter Treaties. Panama gained full control over the Panama Canal in 1999.
History of the United States
After defeating an insurrection by Filipino nationalists, the United States engaged in a large-scale program to modernize the economy of the Philippines and dramatically upgrade the public health facilities. By 1908, however, Americans lost interest in an empire and turned their international attention to the Caribbean, especially the building of the Panama Canal. In 1912 when Arizona became the final mainland state, the American Frontier came to an end. The canal opened in 1914 and increased trade with Japan and the rest of the Far East. A key innovation was the Open Door Policy, whereby the imperial powers were given equal access to Chinese business, with not one of them allowed to take control of China.