These three pictures are part of the large North Pole/Arctic section of the exhibit, which I guess represents Santa’s workshop since I doubt there are any train stations there.
The building materials include gourds, Harry Lauder’s walking stick, eucalyptus leaves, shelf fungus, pine cone scales, alder fruit, cottonwood bark and sliced walnuts.
Best to view in "Original" because other versions resized by Pbase are decidedly unsharp.
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We went to the United States Botanic Garden’s Season’s Greenings exhibit titled “All Aboard,” which showcases historic train stations from around the country made almost entirely from plant materials.
North Pole, Arctic Circle, posted earlier: