Hard lessons from the border

Animals have been blocked from migration, their food chains disrupted. Now, exotic weeds, insects and diseases can use the lengthy scar as a nick point for invasion, ultimately disrupting far more than what human border-crossers can do. Photo by Greg Bulla on Unsplash
MoreThe wall with Mexico will come tumbling down

But one needs to read only a bit of world history to realize that walls can come down as a quickly as they were put up.
Photograph by Greg Bulla, Courtesy of Unsplash
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