The El Camino Real was the primary route between the colonial Spanish capital of Mexico City and the Spanish provincial capitals at San Juan de Los Caballeros, San Gabriel, and Santa Fe. This trail provides a window into the trade and cultural exchanges among Spaniards, other Europeans, American Indians, Mexicans, and Americans that shaped the culture of the American Southwest. Before 1821, Mexico did not permit trade with the United States, and thus trail was often dangerous. This trail was added to the National Historic Trail System in 2000.