National Botanical Gardens-Washinton DC...Has something for everyone~especially lovers of dinosaurs. Check out their Dino Garden, where else can you be surrounded

By a garden that is as close as can be imagined to the time of the dinosaurs, limited vegetation & a lack of blooming flora. Also on view: more orchids than you could dream up, a tropical garden, a desert garden & more. Also worth noting, they have a junior botanist program.