(Spolier Alert: do not read the text below unless you have read the book/seen film)
A Swiss Guard informs Langdon that there are disks around the obelisk in St. Peterâ€™s Square with pictures of each of the directional winds. These were done by Bernini and his workshop. Langdon figures it must be the West Wind, a metaphor for the breath of God (and for social change favored by proponents of enlightened thought).
They race back to the Vatican, arriving at 8.54pm.
The square is crowded with everyone waiting on the announcement of the new Pope.
They frantically search the square, looking for someone matching the Assassinâ€™s profile.
Langdon sees a drunk homeless man lying against one of the fountains in St. Peterâ€™s Square and dismisses it from his mind. When no one appears, Langdon starts to wonder if the Assassin arrives at each location early. Then, a little girl screams, pointing to the drunk homeless man, who turns out to be the second branded Cardinal.
His lungs have been punctured; air is escaping from his ribs and he has been branded with the second word: Air. By now, people, and the media in the piazza, have seen the Cardinal.
The current St. Peterâ€™s Square was designed by GianLorenzo Bernini between 1656 and 1667. He planned the two colonnades which emerge from the Basilica to be like â€œarms of the Mother Church,â€ embracing Catholics as they come to the Vatican and inviting non-Catholics into the fold.
There are 142 huge Doric columns arranged in rows of four on each side of the piazza.
They are spaced apart to allow quick and easy access to the square and provide a psychological break with the outside world.
The first thing in St. Peter's Square was the obelisk or central stone which was placed directly in front of the church in the 1580s. The obelisk was in the chariot racing track of Nero and was the last thing Saint Peter saw before he was killed here on this hill in 67 AD.
Almost one hundred years later Bernini echoed the site's past, by moving the right fountain (designed by his predecessor Maderno) in line with the obelisk and by adding a fountain of his own on the left, to re-create the spina.
The elliptical central area of the square connects to the basilica by a trapezoidal platform from where the Pope speaks on Wednesdays. These aspects make the piazza resemble the chariot racing track where St. Peter was crucified the metaphorical key(s) he was given by Jesus to lead the church.