The Guaita fortress is the oldest of the three towers constructed on Monte Titano, and the most famous. It was built in the 11th century and served briefly as a prison. It is one of the three towers depicted on both the national flag and coat of arms. It was registered as one of the World Heritage Sites in 2008.
Guaita was rebuilt in the second half of the 15th century and in the 16th century has been covered with a sloping roof. It is called the Rocca Guaita and, within its solid walls, protected by double walls (the external wall with merlons and truncated towers at the corners), the population found refuge during sieges.
The upper entrance door, which can be reached by a staircase, is protected by a small wooden construction of 1481. The courtyard contains some pieces of artillery from the Second World War: two mortars, a gift from Vittorio Emanuele II, two 75mm canons fired by the Guardians of the Rocca during national festivities, a gift of Vittorio Emanuele III.
References:The Basilica of Santa Maria in Trastevere is one of the oldest churches of Rome. The basic floor plan and wall structure of the church date back to the 340s, and much of the structure to 1140-43. The first sanctuary was built in 221 and 227 by Pope Callixtus I and later completed by Pope Julius I.
The inscription on the episcopal throne states that this is the first church in Rome dedicated to Mary, mother of Jesus, although some claim that privilege belongs to the Basilica di Santa Maria Maggiore. A Christian house-church was founded here about 220 by Pope Saint Callixtus I (217-222) on the site of the Taberna meritoria, a refuge for retired soldiers. The area was made available for Christian use by Emperor Alexander Severus when he settled a dispute between the Christians and tavern-keepers.
The church underwent two restorations in the fifth and eighth centuries and in 1140-43 it was re-erected on its old foundations under Pope Innocent II.