The Smithsonian is a group of museums and research institutions located in the United States, primarily in Washington, D.C. It was established in 1846 with the mission to increase and diffuse knowledge. The Smithsonian includes 19 museums, 21 libraries, and several research centers, showcasing a wide range of topics from art and history to science and culture. Some of the most popular museums within the Smithsonian include the National Air and Space Museum, the National Museum of American History, and the National Museum of Natural History. The Smithsonian also hosts various exhibitions and educational programs, making it a valuable resource for visitors and researchers alike.