Best Free Museums in Washington DC 2025: Smithsonian & National Collections

Washington DC offers something no other world capital can match — almost unlimited free access to world-class museum collections. The 19 Smithsonian Institution museums on and surrounding the National Mall collectively hold 154 million objects, making it the world's largest museum complex. From the awe-inspiring National Museum of Natural History's Hope Diamond to the National Air and Space Museum's Wright Brothers Flyer and the harrowing National Museum of African American History and Culture, DC's free museums are genuinely incomparable.