Long ago and far away, in 122 AD, Roman Emperor Hadrian began a wall in northern England. It took six years to complete.The purpose of the wall,
according to one website, was to keep out "lawless border prowlers"
from the north.
The wall worked very well for centuries and one can see parts of it even today. My husband and I walked along the wall some years ago on a visit to see his relatives in Scotland. The Scots are now quite civilized and they do not run drug cartels in England.
Hadrian's Wall is a UNESCO World Heritage Site. Although not in my lifetime, Trump's Wall may be declared a UNESCO World Heritage Site some day.