Many countries have Fences/Walls/Barriers to keep the bad people out

http://news.yahoo.com/kenya-begins-construction-somalia-security-barrier-111552026.html
The proposed barrier is the latest in a string of measures Kenya has announced to stem attacks by Somalia's Al-Qaeda-linked Shebab insurgents in the wake of a university massacre in the northeastern town of Garissa.

BULGARIA
http://www.barenakedislam.com/2015/04/07/bulgaria-builds-fence-to-keep-out-surge-of-muslim-illegal-alien-invaders-from-the-middle-east-and-nor

EGYPT
Egypt builds one to keep Gaza terrorist out

USA fence with Mexico

Israel Fence keeping terrorists out

http://www.johnstonsarchive.net/terrorism/terrisraelsum.html