1. Iran marks 40th anniversary of revolution

2. Iranians burn U.S. flags during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Meghdad Madadi/Tasnim News Agency/via REUTERS

3. Iranian people gather as the Iran's President Hassan Rouhani speaks during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Hossein Zohrevand/Tasnim News Agency/via REUTERS

4. Iranian people gather during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Vahid Ahmadi/Tasnim News Agency/via REUTERS

5. Iranian people gather during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Masoud Shahrestani/Tasnim News Agency/via REUTERS

6. Iran's President Hassan Rouhani speaks during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Hossein Zohrevand/Tasnim News Agency/via REUTERS

7. An Iranian woman take selfies during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Vahid Ahmadi/Tasnim News Agency/via REUTERS

8. An Iranian woman carries a picture of Iran's Supreme Leader Ayatollah Ali Khamenei during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Masoud Shahrestani/Tasnim News Agency/via REUTERS

9. Iranians burn U.S. flags during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Meghdad Madadi/Tasnim News Agency/via REUTERS

10. Iran's President Hassan Rouhani speaks during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Official President website/via REUTERS

11. Iranians carry umbrellas during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Vahid Ahmadi/Tasnim News Agency/via REUTERS

12. Iranian people gather during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Masoud Shahrestani/Tasnim News Agency/via REUTERS

13. Iranian people gather as the Iran's President Hassan Rouhani speaks during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Hossein Zohrevand/Tasnim News Agency/via REUTERS

14. Iran's President Hassan Rouhani speaks during a ceremony to mark the 40th anniversary of the Islamic Revolution in Tehran. Hossein Zohrevand/Tasnim News Agency/via REUTERS