Saudi Arabia-Iraq Barrier

A number of years ago, Saudi Arabia built a border fence with Yemen in an attempt to keep out migrant workers from that country.  Now they are building one on their border with Iraq to defend against ISIS infiltration:

Saudi Arabia has been constructing a 600-mile East-West barrier on its Northern Border with Iraq since September.

The main function of the barrier will be keeping out ISIS militants, who have stated that among their goals is an eventual takeover of the Muslim holy cities of Mecca and Medina, both of which lie deep inside Saudi territory, according to United Press International.

This past week, a commander and two guards on the Saudi-Iraq border were killed during an attack by Islamic State militants, the first direct ground assault by the group on the border...

The Saudi "Great Wall" as it's being dubbed by some media outlets, will be a fence and ditch barrier that features soft sand embankments that is designed to slow down infiltrators on foot and are too step to drive a tired-vehicle up, according to the Telegraph of London. It will have 40 watchtowers and seven command and control centers complete with radar that can detect aircraft and vehicles as far away as 22 miles as well as day and night camera installations. 

The barrier system will have five layers of fencing, complete with razor wire and underground motion sensors that trigger a silent alarm. The 600-mile structure will be patrolled by border guards and 240 rapid response vehicles. The Saudis sent 30,000 soldiers to patrol the border in July 2014 after ISIS forces swept into western Iraq and Iraqi guards on the Saudi border fled.