4. Sanaa, Yemen
Sanaa is the largest city in Yemen that is currently extremely unstable. The city is not recommended to visit as it has many violent and conflict activities. The Sanna’s old city has been one of the country’s four World Heritage sites due to country’s four World Heritage sites.
Travelers from all over the world are not advised to this city. Besides this, the city is still at a very high risk of being a target for terrorist activity and kidnapping.