Muscat, Oman's port capital, is surrounded by mountains and deserts on the Gulf of Oman. It combines high-rises and upmarket shopping malls with clifftop structures like the 16th-century Portuguese forts, Al Jalali, and Mirani, which loom above Muscat Harbor. The 20,000-person capacity Sultan Qaboos Great Mosque, with its marble-clad dome and magnificent Persian carpet, is contemporary and marble-clad.