The only country that starts with the letter 'O' is OMAN, which is a country located in the Middle East. It is bordered by the United Arab Emirates to the northwest, Saudi Arabia to the west, and Yemen to the southwest. OMAN has a population of over 4 million people and its capital city is Muscat. The official language is Arabic and the currency is the Omani Rial. OMAN is known for its rich culture and history, as well as its stunning landscapes and beaches.