A March Is Organized In The Southern City Of Ponce By The Puerto Rican Nationalist Party

Natural disasters, including a major earthquake, a tsunami and several hurricanes, and the Great Depression impoverished the island during the first few decades under American rule.

Some political leaders, like Pedro Albizu Campos who led the Puerto Rican Nationalist Party, demanded change. On March 21, 1937, a march was organized in the southern city of Ponce by the Puerto Rican Nationalist Party which turned into a bloody event when the local police opened fire upon the cadets and bystanders. It has since then become known as the Ponce massacre.

Puerto Rico, Guam, the Philippines, and Cuba, ceded by Spain after the Spanish-American War in 1898, and for which the United States compensated Spain an additional $20 million under the terms of Article 3 of the Treaty of Paris. All four of these areas were under United States Military Government (USMG) for extended periods. Cuba became an independent nation in 1902, and the Philippines became an independent nation in 1946.