San Marino (Republic of San Marino/Most Serene Republic of San Marino) is a European mini-state surrounded by Italy. It is located on the northeastern side of the Apennine Mountains. It is also the fifth-smallest country in the world with a land area of 61 square kilometers (23 ½ sq mi). San Marino is said to be the oldest extant sovereign state and the oldest constitutional republic. The capital, the City of San Marino, is located on top of Monte Titano. However, its largest settlement is Dogana within the municipality of Serravalle.
The name San Marino came from Saint Marinus, a stonemason from the Roman island of Rab in present-day Croatia. Saint Marinus found an independently ruled monastic community on Monte Titano in 301 AD.
Unlike other democratic countries with only one ruler in a given period of time, San Marino has two heads of state called the captains regent that serve concurrently and equally in their six-month term. The captains regent are elected by the democratically-elected Grand Council and General Council.
The economy of San Marino is based on finance, industry, services, retail, and tourism. Though it is one of the wealthiest countries in the world in GDP per capita, it has one of the lowest Human Development Index (HDI) scores in Western Europe.
San Marino uses the euro as its currency. Prior to the euro, San Marino used the lira system.