Most tourists are unaware of the Basilica di San Giovanni on the other side of Rome from the Vatican, and would probably be surprised to learn that this Basilica ranks above all other churches in the Roman Catholic Church, even above St Peter's Basilica in the Vatican.
The Basilica of St John Lateran (Basilica di San Giovanni in Laterano) is the cathedral church of Rome and the official seat of the Bishop of Rome, who is the Pope.
As such the Basilica contains the papal throne, although the pope rarely visits and lives over at the Vatican.
There is plenty to admire at the Basilica di San Giovanni. Most tourists visit partly to see the Altar of the Holy Sacrament; here you will see the cedar table that is said to be the one used by Christ at the Last Supper.
Originally built in the 4th century by Constantine and was the Pope's principal residence until the 14th century when he moved across the city to the Vatican.
It is quite confusing that some people refer to the Basilica as Basilica di San Giovanni, others Basilica of St John Lateran; they both are the same place though.
Although not as impressive as St Peter's for most laymen it is well worth a visit if you have time, though the Basilica is a little to the south of the city centre.
Only one of the Hop-on, Hop-off sightseeing buses go here but San Giovanni Metro station is just a 5-minute walk away.
There is a danger in Rome of becoming Basilica lagged, there are so many fine religious buildings all richly decorated and architecturally impressive in Rome that what would be a major sight elsewhere becomes everyday here.
The cathedral where the pope officiates as bishop of Rome, the basilica of San Giovanni in Laterano (St John Lateran) is the oldest of the four major basilicas in the city.
In the Basilica di San Giovanni it is worth seeing the Altar of the Holy Sacrament that contains a cedar table that is said to be the one used by Christ at the Last Supper. The High Altar can only be used by the Pope. There are also six papal tombs.
A visit to the cathedral's 13th century cloisters is worthwhile in order to admire the unique spiral columns and the Cosmatesque mosaics found there. There is a small admission charge to enter the cloisters.
Just outside the church is an octagonal baptistery, ordered by Constantine and which contains some beautiful fifth-century mosaics - well worth a visit. (See below for more details.)
The Basilica San Giovanni is open all day until around 6pm and is free to enter, (with the exception of a small charge if you want to visit the cloisters).
There is little in the way of information provided so you will get much more out of your visit if you invest time and money in a good guide book.
Audio guides are available for rent too for around €5.
The Basilica di San Giovanni is to the south of the city centre by the city walls. It is about 5 minutes' walk from San Giovanni Metro Station on Line A, just 3 stops south of Termini Station and there are plenty of buses too.
There are many bus services serving the Basilica San Giovanni, too many to detail here. Noteworthy is the number 3 tram that connects the Basilica San Giovanni with the Colosseum and the 218 bus that will take you the Appian Way visitor centre.
None of the mainstream hop-on, hop-off sightseeing buses come here with the notable exception of Roma Cristiana, part explained by the fact this operator is part of Opera Romana Pellegrinaggi, a branch of the Vicariate of Rome, an organ of the Holy See, directly overseen by the Carnal Vicar to the Pope.
Like all the other open top sightseeing buses Roma Cristiana operate a bus between the main headline attractions in Rome: the Colosseum, Roman Forum, Vatican and Trevi Fountain. But Roma Cristiana detours further to the south of the city including Basilica San Giovanni.
• Runs every day • The only hop-on bus to visit the Basilica • Free Wi-Fi • Audio commentary in 8 languages
On the other side of the road from Basilica di San Giovanni is an experience you will be sure to remember from your visit to Rome.
The Scala Santa church by Rome standards is a rather small obscure church from outside.
The “Holy Staircase” starts as soon as you walk through the front door and consists of 28 steps of Tyrian marble that legend holds were the actual staircase of Pilate's house, which Jesus descended after being condemned.
According to tradition, Constantine's mother, Helen, brought the steps from Jerusalem to Rome in 326, and they've been in this location since 1589. Today pilgrims from the world over come to climb the steps on their knees.
You cannot ascend the steps on foot, instead you have to go on your knees and climb the steps on your knees to the alter at the top.
Most of the time you are far from alone (see image) and it will take a good chunk of time to go from bottom to top as everyone who makes the climb wants to make a prayer when at the top.
(There is another flight of steps running parallel to the holy steps that you can just walk up.)
Entrance is free, but donations are very gratefully received. The church is open from very early to midday and then again from 3.30pm to 6.30pm.
Another place well worth checking out at San Giovanni and missed by so many is out the back entrance off Basilica San Giovanni, the octagon shaped baptistery.
The modern baptistery is merely that part of the church set apart for baptism. According to ritual, it should be railed off, it should have a gate fastened by a lock, and should be adorned, if possible, with a picture of the baptism of Christ by St. John.
The baptistery at Basilica San Giovanni ticks all the boxes. This baptistery was for many generations the only baptistery in Rome, and its octagonal structure, centred upon the large octagonal basin for full immersions provided a model for others throughout Italy.
It is free to enter and take in the spectacle inside, in complete contrast to the rather dowdy exterior. On the ceiling of the baptistery is the story of the Battle of the Milvian Bridge.