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 (24 sq mi) 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, as the continuation of the monastic community founded on 3 September 301, by stonecutter Marinus of Rab. The constitution of San Marino, enacted in 1600, is the world's oldest constitution still in effect. The country's economy mainly relies on finance, industry, services and tourism. It is one of the wealthiest countries in the world. San Marino is the third smallest country in Europe, with only Vatican City and Monaco being smaller. The climate is Mediterranean with continental influences, having warm summers and cool winters.