You can't visit Washington D.C. without seeing some of the Smithsonian Institution's nineteen museums and galleries. They are the jewels in the crown of this town. If you have the luxury of being able to explore all or most of the Smithsonian branches in D.C., you will see a breadth of art, history, science, and culture unparalleled anywhere in the world. (If you have time only for the top three Smithsonians, they are covered in the next section.) The museums are open every day except December 25, and they are all free.