(From Wikipedia)

The Republic of San Marino traces its origin to the early 4th century CE when, according to tradition, St. Marinus and a group of Christians settled there to escape persecution. The Castellum Sancta Marini is mentioned in the Liber Pontificalis (“The Book of the Pontiffs”) in 755; the oldest document in the republican archives mentions the abbot of San Marino in 885. By the 12th century San Marino had developed into a commune ruled by its own statutes and consuls. The commune was able to remain independent despite encroachments by neighbouring bishops and lords, largely because of its isolation and its mountain fortresses. Against the attacks of the Malatesta family, who ruled the nearby seaport of Rimini, San Marino enjoyed the protection of the rival family of Montefeltro, who ruled Urbino. By the middle of the 15th century, it was a republic ruled by a Grand Council—60 men taken from the Arengo, or Assembly of Families. Warding off serious attacks in the 16th century (including an occupation by Cesare Borgia in 1503), San Marino survived the Renaissance as a relic of the self-governing Italian city-states. Rule by an oligarchy and attempts to annex it to the Papal States in the 18th century marked the decline of the republic. 

The main attraction in San  Marino is the Medieval fortress of Guaita. It is an extensive complex and along the paths you will find many vendors of local crafts, and of course restaurants with stunning views. During the tourist season there is a transport tram that goes from the parking lots at the bottom up to the top. Look for the tram stop signs by the parking lots. Even though San Marino is an independent country, there is no border control. However if you bring your passport you can get a tourist stamp to mark your visit. Today San Marino is the fifth smallest country in the world, and the worlds oldest republic. The population is only 33,000.