The 2015 Nobel Peace Prize remains shrouded in secrecy before Friday's announcement of the winner, but that doesn't stop the annual guessing game about who is in the running.
The Norwegian Nobel Committee, which chooses the laureate, does not name those nominated for 50 years.
"Insofar as certain names crop up in the advance speculations as to who will be awarded any given year's Prize, this is either sheer guesswork or information put out by the person or persons behind the nomination," according to the committee."Information in the Nobel Committee's nomination database is not made public until after fifty years."
However, the committee divulged that there were 273 candidates -- 68 organizations and 205 individuals -- this year.
Here's a look at speculation about the top 10 contenders, beginning with predictions by the director of the Peace Research Institute Oslo, Kristian Berg Harpviken, and concluding with the most likely additional laureates, according to the betting site Betfair.
1. German Chancellor Angela Merkel
German Chancellor Angela Merkel has played a key role in Europe's response to the migrant crisis.
Harpviken puts Angela Merkel at the top of the list for her response to the massive influx of refugees into Europe.
"In a time when many have dodged responsibility, Merkel has shown true leadership and risen above politics, taking a humane approach in a difficult situation," he said.
It's a change in image for Merkel, who previously was dubbed Europe's "Iron Lady" for her hard-line approach to the continent's financial crisis.
The Chancellor since 2005, she is the first woman to hold the post.
Merkel, the daughter of a Protestant minister, grew up in a little town in then-communist East Germany and trained as a physicist.
She entered politics as spokeswoman for East German opposition movement Democratic Awakening during the 1989 revolution.
2. Juan Manuel Santos and Timoleon Jimenez
Colombian President Juan Manuel Santos, left, and FARC leader Timoleon Jimenez, right, in Havana.
Colombian President Juan Manuel Santos and Timoleon Jimenez, the leader of the Revolutionary Armed Forces of Colombia, or FARC, agreed to a path for peace this year, setting the groundwork for a final accord.
The breakthrough came in Havana, Cuba, where officials from both sides had met to try to hammer out a deal.
If a final agreement is reached, it will mark the end of the longest-running insurgency in Latin America, and be a major feather in Santos' cap.
The leftist group began its war against the Colombian government in the 1960s.
3. Dmitry Muratov and the Novaya Gazeta
Dmitry Muratov has been the driving force behind Russian opposition newspaper Novaya Gazeta.
Dmitry Muratov is editor-in-chief and one of the founders of Novaya Gazeta, an independent Russian newspaper.
Despite the killings of some of its journalists, the newspaper continues to criticize President Vladimir Putin and hold him accountable.
In 2007, Muratov was awarded an International Press Freedom Award by the Committee to Protect Journalists, which said he was the "driving force" in the "only truly critical newspaper with national influence in Russia today."
Harpviken said it would be a media first if Novaya Gazetar and its editor receive the Nobel Peace Prize.
"With Russia's state security apparatus severely restricting the space for public expression, drawing attention to its few remaining independent media would send a strong signal," he said.
It would also be a full-circle moment: Former President Mikhail Gorbachev used his Nobel Peace Prize money to start the newspaper in the 1990s.
4. Article 9 Association
Japanese writer Kenzaburo Oe, part of the Article 9 Association, addresses a peace rally last year in Tokyo.
The Article 9 Association is a pacifist group that has been fighting to preserve a Japanese constitutional clause that prohibits war as a means of settling international disputes.
The clause was introduced after World War II and prohibited belligerency by the state.
The awarding of a Nobel Peace Prize to this group could be seen as pointed since it comes shortly after the most dramatic shift in Japanese military policy in 70 years.
In September, Japan's upper house of parliament passed controversial legislation reinterpreting Article 9.
The reinterpretation allows Japan to exercise collective self-defense, enabling the Japanese military, known as the Self-Defense Forces, to fight overseas and defend allies with limited conditions.
"In a region characterized by deep tensions, there are concerns that last year's reinterpretation of Article 9 by the (Shinzo) Abe government and the subsequent 'Peace and Security Preservation Legislation,' passed in September this year, are precursors of armed confrontation," Harpviken said.
5. Jeanne Nacatche Banyere, Jeannette Kahindo Bindu and Dr. Denis Mukwege
Denis Mukwege, a Congolese gynecologist, has helped to provide sanctuary for victims of sexual violence.
Jeanne Nacatche Banyere, Jeannette Kahindo Bindu and Dr. Denis Mukwege work to help rape victims in the Democratic Republic of the Congo.
Mukwege is a gynecologist who has been something of a savior for victims of sexual violence in his native country, providing a rare sanctuary for survivors.
Many travel hundreds of miles to have their physical and psychological wounds healed. Rape is a weapon of war in the region, making his services crucial.
Harpviken said Banyere and Bindu help seek out survivors of sexual violence and provide support, ensuring they receive treatment and help.
"By awarding the trio's local, grass-roots and on-the-ground actions with a Nobel Prize, the Nobel committee has a chance to strengthen the visibility of sexual violence as a global problem," he said.
6. Pope Francis
Pope France has just returned from his first U.S. visit, including a stop in Philadelphia.
Francis is the first non-European pope in the modern era
His empathy and compassion toward the disenfranchised has earned him fans worldwide, and he has shaken up the Vatican, redefined the papacy and breathed new life into the Catholic Church.
Other popes have been peace-loving, writing long treatises against the arms race, campaigning against the American wars in Iraq and sending envoys to search for diplomatic solutions.
But Francis has pleaded pacifism's cause with unusually striking emotion -- while facing provocations such as the rise of ISIS, the conflict in Ukraine, the Gaza war and civil strife in Syria.
Norwegian lawmaker Abid Raja nominated the Pope or this year's prize, and Betfair ranks him the most likely laureate.
7. Mussie Zerai
Catholic priest Mussie Zerai founded Habeshia, an agency to help immigrants to integrate in Italy.
Mussie Zerai acts as a phone contact for migrants crossing the Mediterranean Sea for Europe, passing on the coordinates of their boats to rescuers and coast guards.
The Catholic priest grew up in Eritrea before joining his father in Italy as a 17-year-old political refugee, and he is now based in Switzerland.
Zerai founded Habeshia, the Agency for Cooperation and Development, in Italy in 2006 to provide solidarity for "asylum seekers, refugees and beneficiaries of humanitarian protection."
The agency provides help to integrate immigrants in Italy as well as supporting those returning to their countries of origin. "Above all, our task is to give voice to the voiceless People," it says.
In a 2014 interview with The New Yorker magazine, Zerai downplayed his efforts in the migrant crisis.
"For me, is only service," he said. "I don't have this type of ... what you say? ... pride. No. I am priest. I am pastor of the persons. Even when the people kiss my hand, they don't kiss me. They kiss Jesus Christ. Not me," The New Yorker quoted him as saying.
As well as being a bookmaker's favorite, Zerai was No. 1 on Harpviken's January list of potential laureates.
8. Daisaku Ikeda
Philosopher Daisaku Ikeda is leader of the Japanese Buddhist group Soka Gakkai International.
Daisaku Ikeda is president of the Japanese Buddhist group Soka Gakkai International and a philosopher, writer and educator.
The lay group says it is dedicated to revitalizing Nichiren Buddhism and its "legacy of Buddhist humanism."
"SGI members are committed to promoting the importance of peace and the ideal of respecting the dignity of life and human rights through various activities, such as through holding exhibitions about the threat of nuclear weapons or humanitarian relief activities," the group's website says.
Ikeda also founded the nondenominational Soka school system "based on an ideal of fostering each student's unique creative potential and cultivating an ethic of peace, social contribution and global consciousness."
Soka Gakkai International says: "In (Ikeda's) view, global peace relies ultimately on a self-directed transformation within the life of the individual, rather than on societal or structural reforms alone."
The group quotes one of Ikeda's writings: "A great inner revolution in just a single individual will help achieve a change in the destiny of a nation and, further, will enable a change in the destiny of all humankind."
9. Edward Snowden
Edward Snowden's revelations about National Security Agency activities generated global shock waves.
Edward Snowden -- a former contractor at the U.S. National Security Agency who leaked documents about top secret mass surveillance programs -- is a hero to some, traitor to others.
His 2013 revelations about the scale of the NSA's snooping activities sent shock waves around the globe.
Civil liberties campaigners see him as a champion for privacy of individuals, but the NSA says Snowden's surveillance leaks had a "material impact" on its ability to prevent and detect terror plots.
In June, President Barack Obama signed a bill into law revoking the NSA's authority to collect the phone records of millions of Americans.
Its passage was the culmination of efforts to reform the NSA that blossomed out of Snowden's 2013 revelations.
In July, the White House rejected a petition with more than 167,000 signatures to pardon Snowden, who has said he wants to return to the United States from Russia, where he has asylum.
Snowden is a director on the board of the Freedom of the Press Foundation, working "on methods of enforcing human rights through the application and development of new technologies."
10. Raif Badawi
Saudi activist Raif Badawi received the PEN Pinter Prize's 2015 International Writer of Courage Award.
In 2008, Raif Badawi launched the Free Saudi Liberals website. It didn't take long for the Saudi government to take notice -- detaining him for a day and questioning him about the site.
Yet Badawi kept on writing and talking publicly about his relatively liberal views in the conservative Middle Eastern nation, even after some clerics branded him an unbeliever and an apostate.
The Saudi government came down much harder in June 2012 when it arrested Badawi and sent him to prison. He's been there ever since.
A Jeddah Criminal Court found him guilty in 2013 of insulting Islam through his website and in TV comments, sentencing him to seven years in prison and 600 lashes. He was retried after an appeal, then received an even harsher sentence -- 10 years and 1,000 lashes. He stoically arched his back during his initial public flogging (of 50 lashes) in January, but floggings beyond that have been delayed due to concerns about his health.
Badawi's open talk on religious matters, his standing his ground and Saudi Arabia's punishment drew the attention of human rights advocacy groups, who accused Riyadh of violating his right to free expression. This week, Badawi was honored as the PEN Pinter Prize's 2015 International Writer of Courage.
"What moved me was the contrast between the simplicity of Badawi's liberal aims -- their modesty, almost -- and the ferocity of the punishments they have brought down on him," said British poet, journalist and literary critic James Fenton, who chose to share his PEN Pinter Prize with Badawi. "... Protest has a purpose and -- who knows? -- perhaps even a chance of some success."