National Zoo, 3001 Connecticut Ave., NW, Washington, DC. One of the most kid-friendly places to visit in Washington, DC is the National Zoo where you can see more than 400 different species of animals. No admission fee.
The National Zoo, Washington DC's 163-acre zoological park set within the Rock Creek National Park, features more than 400 different species of animals. The National Zoo is a part of the Smithsonian Institution and admission is FREE! (There is a fee however, for parking in Zoo lots.)