First Stop on my consolation prize visit to The Mall was the National Garden at the United States Botanical Gardens and Conservatory. When I first moved to Metro DC, this was just a grassy plot of land adjacent to the main build and glass conservatory. It was used for spill over parking and temporary logics site when big events took place on The Mall, and little else. In 2006, it was officailly opened to the public as the National Garden, although there were elements still in progress like the Amphitheater.
Yet you can really see the tremendous transformation of the little piece of land from the before and after aerial images. This visit is of a late winter/early spring garden with little happening yet, but you can still appreciate the beauty of the design. I was also delighted to find the little contemplation loggia completed. It is the latest and final major addition to the park.