Each year the United States Botanic Garden has an exhibit called "Season's Greetings, America's Gardens" This year it runs through Sunday January 5th (so there is still time to go see it). There are two parts to it, one part scale models of monuments and notable buildings of Washington DC. These buildings are made out of plant material such as sticks and leaves. The other part has model trains that run through the plants and models of buildings at other botanic gardens in the U.S.
The White House
The Lincoln Memorial
The National Museum of African American History and Culture
The Smithsonian "Castle"
A model train running among the plants.
