1: 1. Afghanistan - Political instability and ongoing violence make it unsafe for tourists.

2: 2. Iraq - High levels of terrorism and conflict make it a dangerous destination.

3: 3. Syria - Civil war and terrorism pose major risks for travelers.

4: 4. Libya - Political unrest and violence make it a risky place for tourists.

5: 5. North Korea - Closed-off regime and harsh penalties for visitors make it dangerous.

6: 6. Venezuela - Economic crisis and high crime rates make it unsafe for tourists.

7: 7. Yemen - Ongoing conflict and high levels of violence make it a dangerous destination.

8: 8. Somalia - Political instability and terrorism pose major risks for travelers.

9: 9. South Sudan - Civil war and humanitarian crisis make it one of the most dangerous countries for Americans to visit.