San Marino, is a state situated on the Italian Peninsula on the eastern side of the Apennine Mountains. It is an enclave surrounded by Italy. Its size is just over 61 km2 with an estimated population of over 30,000. Its capital is the City of San Marino. San Marino has the smallest population of all the members of the Council of Europe.
San Marino is the oldest surviving sovereign state and constitutional republic in the world. It is considered to have a highly stable economy, with one of the lowest unemployment rates in Europe, no national debt and a budget surplus. (source)
Thank you Filippo from Ufficio di Stato per il Turismo!