Central Eastern Europe Serenissima Repubblica di San marino San Marino San Marino, officially the Republic of San Marino (Italian: Repubblica di San Marino), also known as the Most Serene Republic of San Marino (Italian: Serenissima Repubblica di San Marino), is a second smallest country in the world and a European microstate in Southern Europe enclaved by Italy Located on the northeastern side of the Apennine Mountains, San Marino covers a land area of just over 61 km2 (24 sq mi), and has a population of 33,562. San Marino's official language is Italian. Most Serene Republic of San Marino San Marino is a landlocked country but the northeastern end is within 10 km of the Italian city of Rimini on the Adriatic Sea. View of the the fortress of Guaita on Mount Titano. The country's capital city, the City of San Marino, is located atop Monte Titano, while its largest settlement is Dogana within the largest municipality of Serravalle. View of the Guaita defensive wall. The country derives its name from Saint Marinus, a stonemason from the then-Roman island of Rab in present-day Croatia. Born in AD 275, Marinus participated in the rebuilding of Rimini's city walls after their destruction by Liburnian pirates. Marinus then went on to found an independently ruled monastic community on Monte Titano in AD 301; thus, San Marino lays claim to being the oldest extant sovereign state, as well as the oldest constitutional republic. Uniquely, San Marino's constitution dictates that its democratically elected legislature, the Grand and General Council, must elect two heads of state every six months. Known as captains regent, the two heads of state serve concurrently and hold equal powers until their term expires after six months. The country's economy is mainly based on finance, industry, services and tourism. It is one of the wealthiest countries in the world in GDP per capita, with a figure comparable to the most developed European regions. Despite this fact, ranking 44th, its Human Development Index score is the lowest in Western Europe. It is one of only three countries in the world to be completely enclosed by another country (the others being Vatican City, also enclosed by Italy, and Lesotho, enclosed by South Africa). It is the third smallest country in Europe, after Vatican City and Monaco, and the fifth smallest country in the world.[ San Marino is a developed country, and although it is not a European Union member it is allowed to use the euro as its currency by arrangement with the Council of the European Union; it is also granted the right to use its own designs on the national side of the euro coins. San Marino and Italy have engaged in conventions since 1862, dictating some economic activities in San Marino's territory. The highest point in the country, the summit of Monte Titano, is 749 m above sea level. The lowest, the Ausa River (ending in the Marecchia), is 55 m .