The United States emerged as a world power from the economic boom it experienced after WWI. The United States had already experienced an immense strengthening as an imperialist, militarized world power after its victory in the Spanish-American War in 1898 and its colonial, imperialist acquisition of Puerto Rico, the Philippines, and Guam as a result. Because of the Industrial Revolution, the United States was able to be a part of a massive war economy that led to a huge economic boom for the United States. The United States displayed undeniable military strength during WWI and enjoyed great economic and military strength throughout the 1920s, until the the Great Depression hit. This was a result of the strength of the U.S. military and from the U.S. loaning billions of dollars to the Allies. Once the war was resolved, the United States emerged as a world power who was able to begin the process of collecting debts from and holding power over several European nations.