The destroyers-for-bases deal was a transaction agreed upon by the United States and Great Britain during the summer of 1940 that said the U.S. would trade 50 1,200-ton destroyer ships to Great Britain in exchange for naval and air bases that Great Britain had in several different areas all around the world. Some of these bases were located in the Avalon peninsula, Newfoundland's coast and the Great Bay of Bermuda.
Eventually, this deal would be expanded to include other bases located in various parts of the Caribbean. The lease on these bases was agreed to be 99 years free of rent or charge and was agreed upon through correspondence between the U.S.'s then-secretary of state, Cordell Hull, and the British Ambassador in America. This is considered an important moment in World War II, as the agreement marked a major development in the U.S.'s alliance with Great Britain as they fought the Germans off from a major invasion. The trade came about because the U.S. was willing to supply destroyers to Great Britain, but Great Britain preferred not to expend their cash supply which was already in short supply from waging war with Germany. Because of this, they decided to lease out their air and naval bases instead.