Indiana Jones And The Great Circleis a game that rewards exploration. The first large open-world section of your adventure, Vatican City, lets you visit the Sistine Chapel, which you can access using the key that you get from Antonio. The main reason to go here is to visit Sister Catherine and start her quest chain, but there’s an extra puzzle to solve if you poke around a bit more.

The room at the back of the Sistine Chapel has a locked safe. As it turns out, you only need to do a little extra sleuthing to find the combination and get it open.

How To Start The Secret Of Secrets Mystery

You can visit the Sistine Chapel in thesouthern area of Vatican City, as long as you have thepriest disguise and Clerical Keythat you received from Antonio. Take the paththrough the Borgia Gardensand use the key to unlock the main door.

It’s best toget the camerabefore visiting the Sistine Chapel, as there are several photo opportunities here that can earn you extra Adventure Points.

Speak to Sister Catherine on the left side of the Chapel andtake her pictureif you haven’t already, thengo to the back of the roomand open the door on the left.Read the note on the table inside and immediately to the rightto start the Secret Of Secrets Mystery.

Snap a picture of the famous ceiling too while you’re here; you can use it to get more AP later. The best place to take the picture ison the steps next to the seated prieston the left side of the room.

How To Open The Safe In The Sistine Chapel

The note from Nicoletti refers to an original 12th-century manuscript held in the safe across the room. The only clue to the combination is as follows:

Look to the stars and the saints: Peter with the key, then Paul with the sword.

Standing next to the table with the note and facing the safe, you can seethree small statuettesin the room:

As the note suggests,only the statues of Peter and Paul are relevant to the puzzle;you can ignore the statue of Saint Anthony. Pick up the Peter and Paul statues androtate them so that you can see the underside of their bases. Each hastwo planetary symbols painted on them.

Since the angle at which Indy holds the statues means the symbols are upside-down, the order of the symbols (placing Peter first, followed by Paul, as instructed by Nicoletti’s letter) isMars, Mars, Uranus, Mercury.

Theoretically, you can open the safejust by knowing the order of the planets. Mars is the fourth planet from the sun, Uranus is the seventh, and Mercury is the first, so thecombination to the safe is 4471.If you need extra help (or just want to make sure you collect all the available notes before moving on) there’s aPlanetary Chart inside a drawer in the center table.

Location

Nicoletti’s Letter

On the table on the right as you enter the room at the back of the Sistine Chapel.

Hidden Note

Under the book inside the safe.

The manuscript inside the safe isactually a forgery, but picking it up reveals the third and final Mystery Note for Secret Of Secrets, which hints at a dignitary from Germany arriving soon while Mussolini’s forces work to secure control of the Vatican. You’ll also be rewarded with theAdventure Book for the Cutman Skill, which improves the rate at which Indy recovers health.

Once you’ve solved the Mystery,take the stairs at the back of the roomand unlock the door at the bottom with the Clerical Key. Give the priests there the photo that you took of the Sistine Chapel ceiling, thenunlock the exit doorto give yourself an easy way back into the building - it could be useful if you need an escape route later!