intro: With more than 1 billion Catholics worldwide, the face of the church is changing.
It's something the cardinal electors may keep in mind when the conclave to elect a new pope begins sometime in March, said Matthew Bunson, general editor of the Catholic Almanac and author of "We Have a Pope! Benedict XVI."
There are 115 cardinal electors who will vote in this conclave, and they almost always elect one of their own.
Joseph Ratzinger, an intellectual and respected cardinal from Germany, was the front-runner for the papacy in 2005, Bunson said. When elected, he became Pope Benedict XVI.
Coming into this conclave, there are no strong favorites.
"I think the cardinals are going to take their time and deliberate to find the exact person who is needed," Bunson said. "I really do think it is wide open right now, more than ever."
Here's a quick look at some of the possible picks for pope:
quicklist: 1 title: Cardinal Angelo Scola, 71, Italy text: Scola was named the Archbishop of Milan in 2011, a prominent post in the Roman Catholic church.
"If we had to pick a front-runner, it's him," Bunson said. "He first is a brilliant theologian and has the intellectual heft to be pope, which is crucial. He has the clear favor of Pope Benedict.
Milan and Venice together have produced five popes in the past century.
Scola is also committed to promoting an understanding across faiths.
He started the Oasis Foundation in 2004, which helps bridge a dialogue between Christians and Muslims.
Helen Alvaré, a professor of law at George Mason University and an advisor to Pope Benedict XVI's Pontifical Council for the Laity, agreed that Scola will be considered papabili -- an Italian word for someone highly qualified for the papacy.
"It would not be surprise me if a Scola, or another great European mind also was determined to be what was needed for the times," she said.
quicklist: 2 title: Cardinal Angelo Bagnasco, 70, Italy text: The Archbishop of Genoa has a "reputation for intellectual heft," Bunson said.
Bagnasco, two-time president of the Italian Bishops Conference, has a history of taking a strong stance on church doctrine.
In 2007, he was the subject of death threats after he led a campaign against proposed Italian legislation to grant some legal rights to unmarried couples, including people in same-sex relationships.
Italians form the largest voting block in the College of Cardinals, with 25 percent of the seats, and could help propel Bagnasco into the papacy.
quicklist: 3 title: Cardinal Peter Erdo, 60, Hungary text: At 60 years old, Erdo could have a lengthy papacy, bringing stability to the Vatican.
The Hungarian is president of the Council of the Bishops' Conferences of Europe.
When he was named a cardinal by Pope John Paul II in 2003, Erdo said he wanted "to contribute to the strengthening of religious and spiritual life in the face of new challenges and problems that the church in Hungary now faces," the Catholic News Service reported.
Since then, Erdo has had worldwide reach, traveling on behalf of the Vatican.
"He is very much an intellectual, certainly a supporter of the New Evangelization and he represents a staunchly Catholic country," Bunson said. "He is somebody I have been looking at as a real potential dark horse."
Erdo has written about the oppression under a communist regime and has pondered the best ways to restore faith to his country.
In 2006, he wrote a letter to President George W. Bush expressing gratitude for the American support of his predecessor, Cardinal Jozsef Mindszenty, who had been arrested, tortured and later lived for 15 years within the U.S. Embassy in Budapest.
quicklist: 4 title: Cardinal Marc Ouellet, 68, Canada text: The former Archbishop of Quebec, who now heads the Congregation of Bishops, has a deep knowledge of the global workings of the church, Bunson said.
"He has had a major role in the appointment of the church's leaders around the world," Bunson said.
And he points out that at 68 years old, Ouellet has age on his side.
Ouellet is someone who could have "worldwide reach," Alvaré said.
"The man who is chosen for the position he has is someone who is understood to have the presence and the future of the church in mind," she said.
quicklist: 5 title: Cardinal Odilo Pedro Scherer, 63, Brazil text: If the cardinals believe it is time for a pope from Latin America, Scherer is seen as one of the top candidates. Scherer, a German-Brazilian, is the archbishop of Sao Paolo, the largest diocese located in the country with the most Catholics.
He was appointed in 2011 to the Pontifical Council for the Promotion of the New Evangelization and is considered a moderate.
quicklist: 6 title: Cardinal Leonardo Sandri, 69, Argentina text: With a large center of Catholic faithful in Latin America, Sandri could become the first pope from the region.
The 69-year-old, who was born in Argentina to Italian parents, served as a chief of staff in the Vatican, often reading public message when Pope John Paul II was in declining health.
It was Sandri who announced the passing of the pontiff in St. Peter's Square on April 2, 2005.
"He's well-liked around the world," Bunson said.
He currently serves on the Congregation for the Oriental Churches, acting as a liaison with Eastern European Catholic churches.
Sandri is fluent in English, Spanish, Italian, German and French.
quicklist: 7 title: Cardinal Timothy Dolan, 63, New York text: While the thought of an American pope has long seemed impossible, Cardinal Dolan should not be ruled out, Alvaré said.
"History is changing," she said. "We've been at this a while here in the states, [although] not anywhere as long as Europe."
Dolan, an affable cardinal well-known by Catholics in the U.S. and abroad, "has been grappling with some of the leading questions that face the church for the future," Alvaré said.
In September 2012, along with comedian Stephen Colbert, he co-led a discussion on faith and humor at Fordham University.
"If I am elected pope, which is probably the greatest gag all evening, I'll be Stephen III," he told the crowd of students.
Despite Dolan's good standing, Bunson said he has some doubts.
"It strikes me as unlikely, simply because we are the world's last superpower," he said of the U.S. "So I think that might factor in."
quicklist: 8 title: Cardinal Christoph Schönborn, 68, Austria text: The National Catholic Reporter has called Schönborn "among the most interesting figures in the global church."
Schönborn studied under Pope Benedict XVI and has known the pontiff for decades, however, he has exhibited an independent streak, often going against traditional judgment.
Last year, the Austrian stepped in when one of his priests denied a gay man the right serve on parish council after he was overwhelmingly elected.
The cardinal went so far as to host the man and his partner for lunch, The Associated Press reported, and declared him to be "at the right place."
Schönborn has been a critic of the church's handling of its sex-abuse cases. He was rebuked by the Vatican after he reportedly accused Cardinal Angelo Sodano, former secretary of state, of blocking a sexual abuse investigation.
"It should be remembered that in the church, when there are accusations against a cardinal, the competence rests solely with the pope; others may have an advisory role, always with the proper respect for the person," a Vatican statement said, according to the Catholic News Service.
It's the cardinal's tendency to go against the grain in the church that might make him not a viable pick, Bunson said.
Christopher Bellitto, a professor at Kean University in New Jersey who has written nine books on the history of the church, thinks this may work in the Austrian's favor.
"The one who is the most interesting is Schönborn, because he has been hit by both sides," Bellitto said. "You're standing in the middle, and that's a good place to be."
quicklist: 9 title: Cardinal Sean Patrick O'Malley, 68, Boston text: While conventional wisdom says an American will not be elected pope, O'Malley, the archbishop of Boston, has been viewed as a dark horse.
"There are 117 cardinals, and 116 of them want to be pope. I would say the only one that doesn't want to be pope is Sean O'Malley," Thomas Groome, chair of the Department of Religious Education at Boston College, told the Boston Herald.
"I don't think he would be looking for the trappings of power. I think the guys that are looking for it won't get it — at least that's the tradition — and the ones who aren't looking for it are more likely," he said.
The Bostonian is also tech-savvy, a necessary skill for a 21st century pontiff. He tweets to more than 10,000 followers from his @cardinalsean handle.
quicklist: 10 title: Cardinal Robert Sarah, 67, Guinea text: While Cardinals Turkson and Arinze emerged as early favorites from Africa, the buzz has shifted to Sarah, who hails from the western African nation of Guinea.
As president of the Pontifical Council Cor Unum, Cardinal Sarah is tasked with organizing Catholic relief around the world.
In 1979, Sarah was appointed Archbishop of Conakry, making him the youngest bishop in the world. Pope John Paul II nicknamed the 34-year-old the "baby bishop," according to the Vatican website.
quicklist: 11 title: Cardinal Luis Tagle, 55, Manila text: At 55 years old, Tagle is three years younger than Pope John Paul II when he was elected pontiff.
The charismatic Filipino was named a cardinal in Nov. 24, 2012. He served under then-Cardinal Joseph Ratzinger as a member of the International Theological Commission from 1997 until 2002.
Tagle may be the most social media savvy of the bunch. He hosts a YouTube series and maintains a Facebook page.
quicklist: 12 title: Cardinal Oscar Rodriguez Maradiaga, 70, Honduras text: The Archbishop of Tegucigalpa in Honduras is not only well-schooled in theology, but he also holds a diploma in clinical psychology and psychotherapy from Leopold Franz University in Innsbruck, Austria.
He has been a voice in the fight against poverty and has served as the Vatican spokesman to the International Monetary Fund and World Bank on the issue of third world debt.
Rodriguez Maradiaga made entertainment headlines in 2009 after he reportedly criticized singer Ricky Martin for using a surrogate mother to carry his twin boys, saying "you can't just buy or rent life."
He is president of the Catholic charity Caritas International.
quicklist: 13 title: Cardinal Gianfranco Ravasi, 70, Italy text: The Italian cardinal is a "deep thinker" who has worked to foster a dialogue between believers and secular forces, Bunson said.
Ravasi serves as the president of the Pontifical Council for Culture and is one of the most prolific tweeters in the College of Cardinals, sending messages from his @CardRavasi handle several times a day.
As a pope, Ravasi would "be engaged with culture and rebuilding culture and civilization in general," Bunson said. "He would be a powerful pick."
quicklist: 14 title: Cardinal João Bráz de Aviz, 65, Brazil text: Cardinal Bráz de Aviz is another powerful pick from Brazil, according to experts, who think it's a strong possibility the next pope could come from the world's most populous Catholic country.
Cardinal Bráz de Aviz took over as prefect for the Vatican's department for religious congregations in 2011.
In February 2012, the Brazilian was elevated from the Archbishop of Brasilia to cardinal.
He is considered a progressive Catholic voice in the country.
When he was 36 years old, Bráz de Aviz, was shot when he came across an armed robbery.
"This was a very difficult moment when I thought my life would end," he said in a video posted on Rome Reports.
quicklist: 15 title: Cardinal Laurent Monsengwo Pasinya, 73, Congo text: Cardinal Pasinya, one of the older contenders, has been a preacher of peace in his country, particularly during the turbulent 1990s.
"He took an active role in his country's political situation, helping to guide the country in the delicate transition from Zaire to the Democratic Republic of Congo and promoting peace," his biography on the Vatican website says.
In 2012, Pasinya was chosen to preach the Lenten spiritual exercises to the pope, who sent him a letter of thanks and praise, which was posted on the Vatican's website.
"To be able to grasp in your very presence and in your style, Venerable Brother, the particular witness of faith of the Church which believes, hopes and loves on the African continent gave me special joy: a spiritual patrimony that constitutes a great wealth for the entire People of God and for the whole world, especially in the perspective of the New Evangelization," Pope Benedict XVI wrote.
quicklist: 16 title: Cardinal Peter Turkson, 64, Ghana text: Turkson, who hails from Ghana, is one of several African cardinals who may be in the running for the papacy.
He is currently the president of the Pontifical Council for Justice and Peace, a post he was appointed to by Pope Benedict XVI in 2009.
The job has sent Turkson, who speaks six languages, around the world to handle mediations.
"The fact that an African cardinal is a candidate to be elected pope is the statement to the diversity of the church and the remarkable growth around the world," Bunson said.
Turkson discussed the possible of a black pope at a press conference in 2009, following the U.S. presidential election.
"And if by divine providence -- because the church belongs to God -- if God would wish to see a black man also as Pope, thanks be to God," he said.
Francis Cardinal Arinze, from Nigeria, has also been discussed as a potential pope.
quicklist: 17 title: Cardinal Albert Malcolm Ranjith Patabendige Don, 65, Sri Lanka text: Ranjith, a conservative, was elevated from Archbishop of Colombo to Cardinal in 2010.
He has served as a papal ambassador to Indonesia, the country with the world's largest Muslim population. Approximately 88 percent of Indonesians are Muslim, according to data from the Pew Forum on Religion & Public Life.
quicklist: 18 title: Cardinal Willem Eijk, 59, The Netherlands text: While the Dutch have a reputation for being liberal on social issues, Eijk is viewed as a conservative.
The 59-year-old studied medicine and has doctorate degrees in medical bioethics research and philosophy, according to the Vatican website.
Eijk has taught ethics and moral theology. He previously served on the executive board of the association for pro-life doctors in The Netherlands.
He was elevated from the Archbishop of Utrecht to cardinal in February 2012.