Vatican hidden (secret) rooms and passages?

Question

The Vatican is the smallest sovereign state in the world by both area and population and at the same time is considered a place of many mysteries.

Many movies contain episodes of a Vatican containing secret (hidden or otherwise not freely disclosed) rooms or passages for one reason or another. Moreover, some formally secret passages and/or rooms are now known to exist.

The Passetto is a passage that links the Vatican City with Castel Sant'Angelo. Pope Alexander VI crossed it in 1494 when Charles VIII invaded the city, and Pope Clement VII escaped to safety through it during the Sack of Rome, in 1527. - Secret passage (Wikipedia)

An example of one of the Vatican secret (private) rooms can be read about here:

Denied at first, Perrottet pleaded his case, and a bishop re-juggled the pope's schedule so that Perrottet could be quickly snuck in for a brief visit.

Perhaps the most intriguing secret of the Vatican is, surprisingly, a bathroom -- decorated in erotic frescoes -- in the papal apartments. According to Tony Perrottet, author of "A Journey Through the Historic Underbelly of Europe," this bathroom was painted in 1516 by the Renaissance master Raphael and is called the Stufetta Della Bibbiena, the "small heated room of Cardinal Bibbiena," the official who commissioned the work.

"It had been painted over and then restored. Its existence was denied. Art historians had heard of it, but photos of it from the 1930s were murky and dark," said Perrottet. Gaining entry to this bathroom was Perrottet's greatest challenge while researching his book, he said.

Denied at first, Perrottet pleaded his case, and a bishop re-uggled the pope's schedule so that Perrottet could be quickly snuck in for a brief visit.

"It was very exciting," he said. "One of the clerics took me in for five minutes. The room was filled with erotic frescoes. I saw Venus naked doing her hair by the lake, her legs akimbo, and I had to get to the monsignor to step aside to see the most famous one -- Pan pleasuring himself." Perrottet was not allowed to take photographs but made a few drawings.

But because access is only through the Vatican Secret Archives, very few outsiders get to set foot in there. - Secret Rooms, Passageways, Erotic Frescoes of the Vatican

I know other such passages and/or rooms within the Vatican do exist, but cannot find any references to them. In a biography of Pope Pius IX, I read (forgotten the title of the book, but it made reference to a secret passage), about how he wanted to avoid some visitors inside the Vatican and chose to go from one area and another within the Vatican by using a small, but secret passage to get from point A to point B. Unfortunately, he could not open the door from the inside and could only be let out with the aide of the Swiss Guards.

My question is quite simple: Are there any known references of other historically known hidden (secret or otherwise not freely disclosed) passages or rooms within the Vatican?

Answer 1

I found a few..

• Scavi A pagan Roman cemetery located beneath the Basilica of St. Peter. The Vatican Necropolis, or the "scavi," Known for its tombs and their beautifully preserved frescoes, sarcophagi and ancient Christian inscriptions. It contains the grave site for St Peter who died in Emperor Nero's circus/colosseum, as did many early Christian. Christians believed St Peter received leadership of the church directly from Jesus, from God. His grave site was one of the most secret locations for the persecuted christian community and a destination for early christian pilgrims from ~38AD when Peter died to after ~334 AD when Constantine legalized Christianity. When Pope Sylvester showed Constantine where the tomb of St. Peter was, he didn’t share with him where the actual remains were.. Pope Sylvester was still keeping the secret lest future Emperors rescind Emperor Constantine legal status for the religion. Today the Scavi tour is one of the most exclusive tours in the Vatican and only allowed via special permission.

• Secret Archives, The entrance to the Archives, adjacent to the Vatican Library, is through the Porta di S. Anna in via di Porta Angelica (rione of Borgo). The translation of "Archivum Secretum Apostolicum Vaticanum" doesn't mean secret, but more accurately means the Pope's Private Library. Created in the 1700's, closed to outsiders until 1881, when Pope Leo XIII opened them to researchers, more than a thousand of whom now examine some of its documents each year. Still Parts of the Secret Archives remain truly secret, some materials are still prohibited for outside viewing, including everything dated after 1939.

• Tower of the Winds, the Vatican's first astronomy tower. The 200-foot-high structure was built in 1578 so that the pope's astronomers could track the movements of the sun and stars and record the shifting directions of the wind. Because access is only through the Vatican Secret Archives, very few outsiders get to set foot in there. This one perhaps is not so secret, but hidden, or lesser known due to it's location. Inside is a fresco of St Paul's shipwreck on Malta. only St. Peter's Basilica stands higher than the tower. On the wall is a coin-size hole , every March 21, a ray of sunlight points to noon on an eight-pointed rosette in the floor to mark the spring equinox.