A vendor clean souvenirs while waiting for customers on a street in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)

A vendor waits for customers on a street in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)

A vendor shows traditional souvenirs at his shop in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)

A vendor waits for customers on a street in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)

A vendor waits for customers on a street in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)

Souvenirs are seen in a shop in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)

A vendor talks with a customer at his shop in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)

A vendor waits for customers on a street in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)

A vendor waits for customers on a street in the Old City of Sanaa, Yemen, on March 24, 2013. According to local media, Yemen's tourism sector suffered losses estimated at one billion U.S. dollars following the 2011 crisis. Vendors in the Old City of Sanaa, a UNESCO World Heritage Site, said the number of foreign tourists declined by at least 90 percent due to the 2011 unrest that severely undermines security in Yemen. (Xinhua/Mohammed Mohammed)