Building walls really shouldn't be necessary in the 21st Century.
This has nothing to do with what time period you live in. People are slowly but surely figuring out, that the old ways, of separating people by race, religion etc., were not just for narrow minded, prejudiced purposes, but practical, reasonable ones. People are different. The more differences they have, the harder it will be and the longer it will take, to obtain and maintain peace. We need to go back to the old ways!! ( look at Hazzard!)