Pew Research Center on Twitter: "The planned U.S.-Mexico border wall is Donald Trump's least popular policy internationally https://t.co/VhVmbKQyok https://t.co/LyEi4KmeN8" / Twitter
Trump leans globalist in latest wall argument as he says 45 countries have them | Daily Mail Online
7 Modern Border Walls That Separate Countries Around The World
How 65 countries have erected security walls on their borders | Borders, Amazing stories, Around the worlds
A map of the six European countries who have built a wall to stop migrants | indy100 | indy100
6 out of 10 people worldwide live in a country that has built border walls | Transnational Institute
The psychology of separation: Border walls, soft power, and international neighborliness | PNAS
Photos: the Walls Around the World Creating Division
Building walls | Transnational Institute
Why are there not more wall borders for countries throughout history? - Quora
Countries With Border Walls - WorldAtlas
How a Border Wall Could Wreak Ecological Havoc | Science| Smithsonian Magazine
More neighbours make more fences | The Economist
Walled world: Lessons from Europe's border barriers | CBC News
How 65 countries have erected security walls on their borders | Borders, Country, Wall borders
30 Border Walls Around the World Today | Stacker
Border walls: 77 walls or fences around world, many erected since 9/11
The US Is Wrapping Its Border Wall Around the World | The Nation
Border walls: 77 walls or fences around world, many erected since 9/11
Border barrier - Wikipedia
Why countries are walling themselves in – and others out - CSMonitor.com
