The United States Botanical garden, in Washington, DC is a mere five minutes from the US Capitol building. The museum is mostly dedicated to plants, but it has a few displays of animals. Inside are plants from the jungle, desert, rare & endangered plants, and more. In the largest section of the museum is a overhead walkway for which you can stare down at huge jungle trees.
If you like biology, botany, or plant photography, you’ll probably stay at this museum for 45-60 minutes. Photography is permitted, but the lighting is dark so we recommend a tripod or flash. Entrance price is free. Capitol South metro station is nearest to the museum.