Most of the Phoenix Islands were annexed by Great Britain in the late 19th century. The United States claimed Howland and Baker Islands in 1935. In 1937, Britain incorporated all the islands in the Phoenix group, except for Howland and Baker islands, into the Gilbert and Ellice Islands colony. The United States claimed sovereignty over Canton and Enderbury in 1938, but in 1939 entered into an agreement with Britain to form the Canton and Enderbury Islands condominium and exercise joint control over the two islands for a term of 50 years. (The agreement continued in force until 1979, when it was nullified by Kiribati independence.) During this period of joint U.S.-British control, Canton was extensively developed, first as a seaplane-landing site, then later as a refueling station for trans-Pacific civilian and military aircraft. It remained in use until 1958.