A few weeks ago I spotted the Botanic Garden at night and was smitten. It was closed, because everything in DC closes for the evening, but I got to visit this weekend and it was so lovely.
They fill it with poinsettias and Christmas lights for the holidays. It's completely lush and colorful. I think the models of the local landmarks (made from mushrooms, bark, cork, leaves, vines, and other things) are there year-round, and they are fantastic. The Capitol is above and the Washington Monument plus reflecting pool below.
I loved seeing these little terraria in ornaments. I'm making a few of these into glitter snowglobes, they are very cheaply available at craft stores.