And that, if things go according to plan, will have been the last we see of Benedict as leader of the world's 1.2 billion Catholics.
His papacy is expected to end at 2 p.m ET (8 p.m. in Rome).
Benedict, who will be known as pope emeritus, is expected to stay at the Castel Gandolfo papal retreat until the Catholic Church's cardinals elect his successor.
After the successor is chosen, Benedict is expected to live in a former gardener's house at the Vatican to lead a life of prayer.
The cardinals' conclave is expected to begin sometime in March.
Updated at 11:43 a.m. ET
"Dear friends," the pope tells the crowd, according to an English translation, "I am happy to enjoy your sympathy. I give thanks for your friendship and for your affection.
"You know that this is a different day for me than earlier days. I am no longer the pope, but I'm still in the church. I'm just a pilgrim who is starting the last part of his pilgrimage on this Earth.
"And with all my heart and prayer and love, and with my thoughts and strength, I would like to work for the common good ... and feel very much supported (by you). ... Thank you all very much.
"So accept my blessing. May god bless you in the name of the Father, the Son and the Holy Spirit.
"Thank you all. Good night. Thank you all."
With that, as bells ring and the crowd cheers, he turns around and re-enters the retreat.
Updated at 11:38 a.m. ET
Benedict has appeared on the balcony. This is expected to be his last public appearance as pope.
Massive amounts of flag-waving from the crowd now. The pope stretches out his hands.
Updated at 11:34 a.m. ET
To give you an idea of how big this crowd is relative to the space available to it: In a town of about 9,000 residents, about 10,000 people are now in or near the village square.
Updated at 11:33 a.m. ET
Benedict is out of the car, and after shaking a hand or two, is walking into the papal retreat in the town of Castel Gandolfo.
The thousands of people waiting in the village square -- many waving Vatican flags -- are waiting for him to appear on the residence's balcony.
Updated at 11:30 a.m. ET
A car is now taking Benedict to the papal retreat at the Italian town of Castel Gandolfo.
He'll get a warm greeting in the town after a roughly 2-kilometer drive. Thousands of people have been standing in the village square for hours, ready to greet him and perhaps hear him say something from the balcony of the papal retreat.
That address from the balcony could in the next 15 minutes or so.
Updated at 11:27 a.m. ET
Benedict is off the helicopter. Standing just outside the helicopter, he's greeting a delegation at the heliport in the Castel Gandolfo area.
Updated at 11:24 a.m. ET
The helicopter, having circled the Vatican as bells rang for the pope in the city-state, has landed in the Castel Gandolfo area. Benedict is due to be greeted by Castel Gandolfo's mayor before a vehicle takes him to the papal retreat, where he'll greet the 10,000 people waiting for him.
Updated at 11:15 a.m. ET
Benedict, minutes ago, sent what may be his final Twitter post as pope:
"Thank you for your love and support. May you always experience the joy that comes from putting Christ at the centre of your lives," he tweeted.
He collected about 2 million Twitter followers since his accounts opened late last year. More than 1.5 million of those follow the English language account.
Updated at 11:08 a.m. ET
Bells ring in Vatican City as the helicopter carrying Benedict takes off.
About 10,000 people await him in the town of Castel Gandolfo, where Benedict should land in 10-15 minutes from now.
Updated at 11:04 a.m. ET
And now, Benedict's last moments as pope in Vatican City. He's aboard the helicopter, which will take off soon.
Updated at 11 a.m. ET
About 15 minutes behind schedule, a motorcade has now taken Benedict away from the area of his papal apartments.
Updated at 10:58 a.m. ET
More Vatican staff greet the pope in the San Damaso courtyard, and the applause from the public continues. The ovation has been going on for about two minutes.
The pope has now entered a black car that will take him to a helicopter, which will send him to Castel Gandolfo 15 miles away.
Updated at 10:56 a.m. ET
Benedict's journey out of the Vatican has begun. He just finished shaking hands with and saying goodbye to some staff members, and now he's walking outside. He'll be taken to a helicopter.
Crowds applaud as goes outside.
Updated at 10:42 a.m. ET
Here's the rough timeline that we have of the events that remain in Benedict's last hours as pope:
-- 10:45 a.m. ET: Pope departs courtyard of San Damaso at the Vatican, and is driven to a heliport.
-- 11 a.m. ET: Helicopter departs for Castel Gandolfo, about 15 miles southeast of the Vatican. He'll remain at a summer papal residence at Castel Gandolfo until his successor is chosen.
-- 11:15 a.m.: Helicopter is due to arrive at Castel Gandolfo.
-- 11:30 a.m.: Benedict greets the crowd and is expected to make a brief salute from a balcony at the Castel Gandolfo residence.
-- 2 p.m.: Benedict ceases to be pope, and the Swiss Guard departs from him. He will continue to be guarded by security personnel, but not by the Swiss Guard.
Updated at 10:22 a.m. ET
We're about 20 minutes from the moment Benedict will start leaving the Vatican for the papal resort in the Italian town of Castel Gandolfo.
What kind of influence will Benedict have over the choice of his successor? Not direct influence, CNN contributor the Rev. Edward Beck says, noting that Benedict will be in seclusion and the cardinals' conclave is to be conducted in secret.
But perhaps he will have had some indirect influence just because he appointed 67 of the roughly 115 cardinals who will be making the selection.
"Many of them would be in the same stream of consciousness, the name theology, the same thought pattern as Benedict, at least theologically perhaps," Beck said of the 67 cardinals that Benedict appointed during his eight years as pope.
Beck also wondered whether, because Benedict is still alive -- he'll be the first living ex-pope in nearly 600 years -- the cardinal electors' choices will be influenced by a desire to respect Benedict. That is to say, whether they'll select someone aligned with Benedict theologically because they don't want to disrespect the living ex-pontiff.
"It's a question I would have, because we haven't had this obviously in 600 years," Beck said.
Updated at 9:49 a.m. ET
There's a "party atmosphere" at Italy's Castel Gandolfo, the seaside papal resort town where, starting tonight, Benedict will be in seclusion until his successor is chosen, CNN's Becky Anderson reports.
About 10,000 people have gathered in the village square, awaiting his arrival set for this evening, according to Journalist Barbie Nadeau.
A banner with solver balloons reads, "Thank you Benedict -- we are with you."
Area residents, many of whom have worked at the papal retreat in the town, have gathered to see what is expected to be Benedict's last public appearance as pope. Benedict is expected to appear on a balcony of the papal retreat Thursday evening, shortly before the moment he resigns. In anticipation of his appearance, a banner has just been unfurled below the balcony.
We're about an hour away from the moment that Benedict will leave the Vatican and eventually embark on a helicopter trip to Castel Gandolfo, about 15 miles southeast of the Vatican.
Updated at 8:32 a.m. ET
We've just gotten a clarification on the number of cardinals eligible to vote for the next pontiff: 115, says Vatican spokesman the Rev. Federico Lombardi.
Two of them might be too sick to attend the conclave, though some arrangements may be made to enable them to vote, Lombardi said.
He did not name the two cardinals. He also didn't say for sure that they wouldn't attend the conclave, and he didn't describe how they might be allowed to vote if they don't attend.
Lombardi's comments came during a Vatican press briefing about Benedict's last day as pope and the coming election of a new pontiff has ended. That briefing has just ended.
Updated at 8:22 a.m. ET
Regarding the Fisherman's Ring, a symbol of office that is due to be destroyed after Benedict resigns tonight, a Vatican spokesman says Benedict has the right to wear it until 8 p.m. Rome time.
Vatican spokesman the Rev. Federico Lombardi says he does not know whether the pope will be wearing it on his helicopter ride to Castel Gandolfo -- the retreat where Benedict will be staying until a successor is chosen -- or whether he'll leave it at Vatican's papal apartments.
Updated at 8:15 a.m. ET
A media briefing at the Vatican continues, and a Vatican spokesman has recently finished talking about when Benedict will learn the identity of his successor. The answer: The same time the rest of the world finds out.
Benedict will not get any advance notice of who his successor will be when he is elected during a conclave that's due to begin in March, Vatican spokesman the Rev. Thomas Rosica says.
Starting tonight, Benedict is expected stay at a seaside papal retreat, Castel Gandolfo, until a successor is named. Then, with a title of pope emeritus, he will retire to a former gardener's house at the Vatican to lead a life of prayer, likely removed entirely from public life.
Read this article for more information on what Benedict's retirement is expected to be like.
Updated at 8:04 a.m. ET
Ah, conclave secrecy. What kind of precautions will the Vatican take to shield cardinal electors from the temptation of leaking information to the public when they gather to elect the next pope in March? That's one of the topics that Vatican spokesmen are addressing now in a news conference on Benedict's last day as pope.
As we noted earlier in this post, cardinal electors will be forbidden to communicate with the outside world during the conclave. A few minutes ago, Vatican spokesmen declined to say whether BlackBerrys, iPhones and laptops would be taken away from cardinals when they are in the conclave.
There is no internet access inside Santa Marta, where the cardinals will stay during the conclave, the Rev. Federico Lombardi said.
Updated at 7:50 a.m. ET
Speaking of Twitter, the pope -- who has collected more than 2 million Twitter followers on various language feeds since joining the social media service late last year -- will send his final tweet this afternoon Rome time, Vatican spokesman the Rev. Federico Lombardi told reporters minutes ago.
Then, the account @Pontifex will go dormant until the next pope decides whether he wants to use it, Lombardi said.
Updated at 7:36 a.m. ET
The days ahead will be busy -- but publicly quiet -- for the cardinals who have to elect a new pope. A tweet by of them illustrates this.
Cardinal Gianfranco Ravasi of Italy, who commentators have speculated might be a candidate for the papacy, has signaled to his Twitter followers that he'll be leaving them for a few days.
Cardinals are forbidden to communicate with the outside world -- now including by Twitter -- during the conclave to elect a new pope.
Updated at 7:23 a.m. ET
More than 140 cardinals were at this morning's meeting with the pope, Vatican spokesman the Rev. Thomas Roscia says at a press briefing.
That includes both cardinals who will be eligible to choose the next pope, and those who are not. To be eligible to vote in the conclave that is expected to begin in March, a cardinal must be under the age of 80.
Not all of the electors, however, were at today's meeting. Some cardinals from around the world have still to arrive at the Vatican for the coming conclave.
At least 115 cardinals are eligible. Benedict appointed 67 of them.
Updated at 7:10 a.m. ET
When the pope met with the cardinals this morning, many of them will be the ones who will chose his successor during a conclave that is expected to start at the Vatican sometime in March. (Some of the cardinals, on the other hand, are too old too be eligible to vote.)
Cardinal Roger Mahony, the retired archbsihop of Los Angeles, was at the meeting. When he greeted the pope, he asked Benedict to pray for the people of Los Angeles, according to a tweet from Mahony.
"He grasped my hand and said "Yes"!!" Mahony tweeted.
Updated at 6:57 a.m. ET
Although this is his last day, the pope is still at work.
This includes receiving resignations and nominating bishops. Today he accepted the resignation of Mons. José Ángel Rova as bishop of Villa Maria, Argentina, and nominated Samuel Jofré to replace him.
He also nominated Mons. Joseph Dinh Duc Dao to be auxiliary bishop of Xuân Lôc, Vietnam - apparently his final official act as pope.
Posted at 5:25 a.m. ET
On the final day of his papacy, Pope Benedict XVI met with cardinals at the Vatican on Thursday, saying "I will continue to serve you in prayer."
After the pontiff completed his remarks, the cardinals greeted him individually, shaking hands and sharing a few words with the retiring head of the Catholic Church.
Benedict announced on February 11 that he would step down, becoming the first pontiff to leave the job alive in 598 years.