Saudis build 1,000-mile Yemen border fence
9 April 2013 Last updated at 23:07 BST
Saudi Arabia is building a fence, over 1,000 miles long, in order to seal off its troubled frontier with Yemen.
The BBC has been told by Saudi border guards that security on the Yemeni side of the border has all but disappeared since the revolutions of the Arab Spring.
The BBC's Frank Gardner returned to Saudi Arabia to cover the story, for the first time since he was shot by militants in 2004.