From 7 to 77: There's been an explosion in building border walls since World War II

At the end of World War II, there were seven border walls or fences in the world. By the time the Berlin Wall fell in 1989, there were 15. Today, there are at least 77. Border walls have been used through history to separate warring nations, protect trade routes andrepel migrants. Here are examples.

     

 

 


Source: USA Today