the basilica of Saint John Lateran was built under pope Melchiade (311-314). It is the oldest surviving church in the world. Due to the fact that the pope is also the bishop of Rome, Saint John in Lateran is also Rome's Cathedral.
The present structure of the Basilica resembles the Saint Peter's basilica. The original plan had already five aisles. The ancient church was residence of the popes until the coming back from the exile in Avignone (1377), when it was moved to the Vatican. It was pillage-stock of the Visigoths (410), the Vandals (455); the earthquake in 896 caused the central aisle roof to collapse (rebuilt under pope Sergio III in 904-911).
Put on fire in 1308 first and in 1361 then, it was remade under the pontificate of Gregorio XI (1370-1378), following the plan of the ancient structure that had by then become a ruin. The repair works continued during the entire fifteenth century and the sumptuous ceiling was realized in 1562.
Sisto V (1585-1590) ordered the construction of the Blessings Lodge (positioned at the end of right side aisle), and the making of the Lateranense building assigning the project to Domenico Fontana.
After about 140 years Pope Innocenzo X Pamphili (1644-1655) decided in 1646 to bring the cathedral to new splendour entrusting Francesco Borromini of the repair. The architect was supposed to finish the works in time for the Holy Year of 1650 and had to reserve (according to the pacts with the pope) the structure of the ancient Basilica of St John Lateran. The artist put 12 niches spaced up by 5 huge arches supported by as many pillars in the mid aisle.
The great statues of the Apostles that we can admire today in the borrominian niches were made by sculptors of the late baroque in the beginning of 1700.
In 1731 Pope Clement XII summons a competition for the new façade of Saint John in Lateran. The winner without too much merit was the Florentine Alessandro Galilei who in 1735 finishes the works of the present façade. Under the ogival tabernacle (at the end of the central aisle, in the transept) is the papal altar where only the Pope can give mass. Above the sacramental altar there's a fragment of the table on which Jesus consumed the last supper. The Cathedral hosts also Jesus' blood, brought to Rome by centurion Longino. Numerous are the chapels of noble families realized by some of the best artists of the different epochs. In the intermediate right aisle, close to the first pillar, one can admire Boniface VIII proclaims the Jubilee of 1300, a fresco made by Giotto.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.