Fort Sam Houston has been San Antonio's Army post since 1845. Originally located in the city, elements of the post began moving to Government Hill in 1876. Fort Sam Houston became one of America's most important military installations, witnessing the end of the Indian Wars, the Spanish-American War, the birth of military aviation, World Wars I and II, the Korean War, and the Vietnam War. "Fort Sam" contributed more than one million soldiers and airmen to the defense of the United States, including many of its most distinguished leaders. Its contributions to the nation merited its designation as a National Historic Landmark in 1974. More than 800 historic buildings are within its boundaries—more than at Colonial Williamsburg and the largest collection on any installation within the Department of Defense. Images of America: Fort Sam Houston portrays the fort during its first hundred years on Government Hill.