What country allowed the US to build military bases?

The Platt Amendment codified relations between the United States and Cuba after the Spanish-American War. Introduced and signed by both countries in 1901, and added to the 1902 Cuban Constitution.

The Platt Amendment outlined the role of the United States in Cuba and the Caribbean and also ensured that Cuba sell or lease lands to the United States necessary for coaling or the development of naval stations, which in 1903 included a coaling and naval station at Guantanamo Bay.