City of San Marino was fortified and protected by three belts of fortifications erected at different times. The first zone (around strengthening Guaita) includes an outer wall of the fortress and pulled up to the ridge of rock, where stood the ancient church Pieve. Within this zone there is an ancient tank, the so-called "pits", which served for the water supply.

The second zone was in action at the beginning of the XIV century, but was built in parts: the oldest part of it relating to the XIII century, surrounded the city, including a modern area of ​​the Government Palace (a fortress of honor). From the top of the fortress offers a magnificent view of the surroundings down to the Adriatic coast.

With the growth and expansion of the city most of the ancient wall was destroyed. By the end of the 50s of the twentieth century in the ancient fortification wall was a prison, and later the city authorities have arranged a museum. During national holidays from the bastions of old cannons firing.

Pentagonal fortress of Montale, was built much later, it is slightly apart and surrounded by forest. Entrance to the tower is now closed.

Gate of San Francesco, also called Gate del Loco, built in 1361, served as the outpost. In 1451 they were completely rebuilt and then restored in 1581, when the outer gate were built. The initial gate opening has been raised with the construction of the tower with machicolations gear. From inside the gates smashed the arms of San Marino and the family Feltreska.

Gates della Rupe, or, as they are called, Gates degli Omerelli, were built in 1525; subsequent restoration was carried out in 1589. The large castle tower of rectangular shape placed artillery. On the square in front of the gate stands the round tower smaller, in ancient times served as a powder magazine, and later turned into a windmill.