1. Aleppo Citadel: Located in the center of Aleppo, this citadel is one of the oldest and largest castles in the world. The origins of the Citadel date back to the 3rd millennium BC. It is home to many mosques, museums, and other monuments.
2. Palmyra: An ancient city located in the desert of Homs, Palmyra is home to many Roman ruins, including the Temple of Bel, the Valley of Tombs, and the Arch of Triumph.
3. Krak des Chevaliers: This Crusader castle, located in the Homs Governorate, is considered one of the best preserved medieval castles in the world.
4. Umayyad Mosque: This mosque, located in Damascus, is one of the oldest and largest mosques in the world. It was built by the Umayyad caliphs in the 8th century.
5. Bosra: This is an ancient city located in the southern part of Syria. It is home to many Roman ruins and monuments, including the magnificent Roman theatre.