(CNN) — (CNN) -- Here's a look at what you need to know about some recent cases of foreign governments detaining U.S. citizens.
Alan Gross December 2009 - Alan Gross is jailed while working as a subcontractor on a U.S. Agency for International Development project aimed at spreading democracy. His actions are deemed illegal by Cuban authorities. He is accused of trying set up illegal Internet connections on the island. Gross says he was trying to help connect the Jewish community to the Internet and was not a threat to the government.
August 2010 - While on a trade mission in Cuba, New Mexico Gov. Bill Richardson presses Cuba to free Gross.
March 12, 2011 - Gross is found guilty and sentenced to 15 years in prison for crimes against the Cuban state.
March 30, 2011 - Former President Jimmy Carter visits Cuba and tries to secure Gross' release on humanitarian grounds, arguing that Gross' mother and daughter are battling cancer. He is unsuccessful.
September 7-14, 2011 - Bill Richardson visits Cuba on a private mission to win the release of jailed American contractor Alan Gross. He is unsuccessful.
February 18-20, 2013 - A U.S. congressional delegation, led by Senator Patrick Leahy, visits Cuba and meets with Raul Castro in an effort to free Gross. They are unsuccessful.
16 American NGO Employees December 2011 - Egyptian authorities carry out 17 raids on the offices of 10 nongovernmental organizations. The Egyptian general prosecutor's office claims the raids were part of an investigation into allegations the groups had received illegal foreign financing and were operating without a proper license.
February 2, 2012 - In a letter to Secretary of State Hillary Clinton and Defense Secretary Leon Panetta, 41 members of Congress urge the administration to withhold further aid to Egypt until the country's leadership lets the offices of those organizations reopen and returns seized property.
February 5, 2012 - Forty-three people, including 19 Americans, face prosecution in an Egyptian criminal court on charges of illegal foreign funding as part of an ongoing crackdown on NGOs. The defendants include 19 Americans, five Serbs, two Germans, three Arabs and Egyptians. Among the American defendants is Sam LaHood, International Republican Institute country director and the son of U.S. Transportation Secretary Ray LaHood.
February 15, 2012 - U.S. State Dept. confirms there are 16 Americans being held not 19 as the Egyptian government had announced.
February 20, 2012 - South Carolina Senator Lindsey Graham and Arizona Senator John McCain meet with top Egyptian military and political leaders in Cairo. In an interview with CNN, Senator Graham says that he is optimistic for a positive resolution in the near future.
February 26, 2012 - Formal reading of the charges against the NGOs. None of the sixteen detained Americans appear in court.
February 29, 2012 - The travel ban is lifted.
March 1, 2012 - A group from the 43 detainees including American, Norwegian, German, Serbian and Palestinian activists leave Cairo after each posted 2 million Egyptian pounds bail.
March 8, 2012 - Trial resumes and is adjourned until April 10. Robert Becker, an employee of the National Democratic Institute (NDI), is the lone American to appear in court.
April 10, 2012 - Trial is adjourned.
April 20, 2012 - CNN is told Egyptian officials have filed global arrest notices with Interpol for some of the Americans involved in the NGO trial.
June 5, 2012 - The trial resumes and among the defendants to appear in court are two Americans; Sherif Mansour, a recently naturalized American citizen born in Egypt and former employee of Freedom House, and Robert Becker, formerly with National Democratic Institute (NDI).
June 4, 2013 - An Egyptian court sentences a total of 43 NGO workers, including several Americans and other foreigners. The court sentences 27 NGO workers in absentia to five-year sentences; 11 to one-year suspended jail sentences; and five others to two-year sentences that were not suspended, according to state-run newspaper Al Ahram.
UC-Berkeley Grads July 31, 2009 - Three graduates from the University of California at Berkeley, Sarah Shourd of Oakland, California, Shane Bauer, of Emeryville, California, and Joshua Fattal, of Cottage Grove, Oregon, are detained in Iran after hiking along the unmarked Iran-Iraq border in northern Iraq's Kurdish region.
August 11, 2009 - Iran sends formal notification to the Swiss ambassador that the three American hikers have been detained. Switzerland represents the United States diplomatic interests in Iran since the U.S. and Iran do not have diplomatic relations.
September 22, 2009 - Iranian President Mahmoud Ahmadinejad publicly insists that the American hikers represented illegal entry and that he has no control over the case.
October 2009 - The Iranian government allows a Swiss diplomat to visit them at Evin Prison.
November 5, 2009 - U.S. Secretary of State Hillary Clinton meets with the detainees' families.
November 9, 2009 - Iran charges the three with espionage.
December 14, 2009 - The Iranian Foreign Minister of Affairs Manouchehr Mottaki states the three will stand trial.
February 2, 2010 - Iranian President Mahmoud Ahmadinejad announces the possibility of an exchange for Iranians serving sentences in America.
February 3, 2010 - Secretary of State Hillary Clinton says that there are no negotiations taking place between Washington, D.C. and Iran regarding prisoner exchanges.
March 9, 2010 - The families of the three detained hikers speak by phone to the hikers for the first time since they were jailed.
May 20, 2010 - The detainees' mothers are allowed to visit their children.
May 21, 2010 - The mothers are allowed a second visit, and the detained hikers speak publicly for the first time at a government-controlled news conference.
August 1, 2010 - Iran restates the three should be tried for illegal entry to Iran.
August 5, 2010 - Reports surface that Shourd is being denied medical treatment.
September 14, 2010 - Sarah Shourd is released on humanitarian grounds from Evin Prison on $500,000 bail.
September 19, 2010 - Shourd speaks publicly to the press in New York.
September 24, 2010 - Shourd and her mother meet with Iranian President Mahmoud Ahmadinejad in New York to discuss the release of her friend, Josh Fattal and her fiancé, Shane Bauer.
November 6, 2010 - Josh Fattal, Shane Bauer and Sarah Shourd are scheduled for trial on charges of spying in Iran's Revolution Court, but the trial is postponed.
November 27, 2010 - Two days after Thanksgiving, Josh Fattal and Shane Bauer are allowed to call home for the second time. Each call lasted about five minutes.
January 31, 2011 - Iran issues a summons for Sarah Shourd to return to Tehran for a trial on espionage charges. The trial is scheduled for February 6, 2011.
February 6, 2011 - Josh Fattal and Shane Bauer's trial begins. Sarah Shourd has not responded to a court summons to return to stand trial.
May 4, 2011 - Sarah Shourd announces she will not return to Tehran to face espionage charges in a court hearing scheduled later in the month.
May 11, 2011 - The trial is delayed again after the suspects are not brought from the prison to the courthouse.
July 31, 2011 - Fattal and Bauer's final hearing takes place as closing arguments are presented.
August 20, 2011 - Josh Fattal and Shane Bauer each receive five years for spying and three years for illegal entry, according to state-run TV. They have 20 days to appeal.
August 28, 2011 - Attorney Masoud Shafiee announces that he has filed an appeal in the case. He says it could take from a few days to few months for the court to respond.
September 13, 2011 - President Mahmoud Ahmadinejad tells NBC in an interview, "We tried last year to free one of the three persons and we are also trying to make arrangements for the freedom of the other two. I think these two persons will be freed in a couple of days." Josh Fattal and Shane Bauer will be released from Tehran's Evin prison after a $500,000 bail is paid for each of them, their attorney, Masoud Shafiee, says.
September 14, 2011 - A Western diplomat tells CNN that an Omani official is en route to Tehran to help negotiate the release of Josh Fattal and Shane Bauer. Oman helped secure the release of Sarah Shourd in 2010.
September 21, 2011 - Josh Fattal and Shane Bauer are released from prison on bail of $500,000 each and their sentences are commuted. Their lawyer declined to say who had paid the bail.
September 25, 2011 - Josh Fattal and Shane Bauer arrive back in the United States.
Saeed Abedini September 26, 2012 - According to the American Center for Law and Justice, Saeed Abedini, an American Christian pastor who was born in Iran and lives in Idaho, is detained in Iran. The group says that Abedini's charges stem from his conversion to Christianity from Islam 13 years ago and his activities with home churches in Iran.
January 2013 - Abedini is sentenced to eight years in prison, on charges of attempting to undermine the Iranian government.
Amir Mirzaei Hekmati December 17, 2011 - Iran's Intelligence Ministry claims to have arrested an Iranian-American working as a CIA agent, according to state-run Press TV.
December 18, 2011 - Iran's semi-official Fars news agency broadcasts a video in which a young man says his name is Amir Mirzaei Hekmati, and that he joined the U.S. Marine Corps and worked with Iraqi officers.
December 19, 2011 - The U.S. State Dept. confirms the identity of the man detained in Iran and calls for his immediate release.
December 20, 2011 - Hekmati's family says that Hekmati was arrested in August while visiting relatives in Iran. The family asserts that they remained quiet about the arrest at the urging of Iranian officials who promised his release.
December 27, 2011 - Hekmati's trial begins in Iran. Prosecutors accuse Hekmati of entering Iran with the intention of infiltrating the country's intelligence system in order to accuse Iran of involvement in terrorist activities, according to the Fars news agency.
January 9, 2012 - An Iranian news agency reports that Hekmati is convicted of "working for an enemy country," as well as membership in the CIA and "efforts to accuse Iran of involvement in terrorism." He is sentenced to death.
End of January 2012 - Behnaz Hekmati, Amir Hekmati's mother, travels to Iran alone and sees her son, according to sources close to the family.
March 5, 2012 - An Iranian court dismisses a lower court's death sentence for Hekmati and orders a retrial. Hekmati remains in prison.
September 2013 - In a letter to U.S. Secretary of State John Kerry, Hekmati says that his confession was obtained under duress.
Robert Levinson March 8, 2007 - According to his family, retired FBI agent Robert Levinson is last seen on Iran's Kish Island during a business trip.
June 1, 2007 - President George W. Bush says he is "disturbed" by the lack of information Iranian officials have provided on the case.
December 2007 - The Iranian government repeats that they do not know what happened to him.
2010 - Levinson's captors send a "proof of life" videotape and photographs of him to his family. The images are released to the public in 2011.
March 3, 2011 - Secretary of State Hillary Clinton says that evidence is growing that Levinson is alive and being held somewhere in southwest Asia.
January 8, 2013 - Bob Levinson's family releases photographs of Levinson wearing a jumpsuit and holding signs.
September 2013 - During an interview with CNN's Christiane Amanpour, Iranian President Hassan Rouhani says there is no news of Levinson but speaks of cooperation and gathering information to find his whereabouts.
Kenneth Bae December 11, 2012 - U.S. officials confirm that American citizen Kenneth Bae has been detained in North Korea for over a month.
April 30, 2013 - North Korea's Supreme Court sentences Bae to 15 years of hard labor for "hostile acts" against the country.
August 27, 2013 - The State Department says that Ambassador Robert King will travel to Pyongyang at North Korea's invitation and ask for Bae's pardon on humanitarian grounds.
August 30, 2013 - North Korea rescinds its invitation for King to travel to North Korea and try to secure the release of Bae.
October 11, 2013 - Kenneth Bae meets with his mother in North Korea. This is the first time his family has been able to see him for almost a year since Bae's November 3 arrest.
Aijalon Gomes January 25, 2010 - Aijalon Mahli Gomes, of Boston, is detained in North Korea after crossing into the country illegally from China. He had formerly taught English in South Korea.
April 7, 2010 - He is sentenced to eight years of hard labor and ordered to pay a fine of 70 million North Korean won or approximately $600,000.
July 10, 2010 - Gomes is hospitalized after attempting to commit suicide.
August 25-27, 2010 - Former President Jimmy Carter arrives in Pyongyang, North Korea, with hopes of negotiating for Gomes's release.
August 27, 2010 - Carter and Gomes leave Pyongyang after Gomes is granted amnesty by Kim Jong Il for humanitarian purposes.
Euna Lee and Laura Ling Prior to this event, no Americans had ever been tried in North Korea's Supreme Court.
March 17, 2009 - Journalists Euna Lee and Laura Ling cross into North Korea, are apprehended by North Korean soldiers, and charged with illegal entry to conduct a smear campaign.
June 4, 2009 - They are sentenced to 12 years hard labor in a North Korean prison with no forgiveness and no appeal allowed.
August 4, 2009 - Former President Bill Clinton travels to Pyongyang on a private humanitarian mission to meet with North Korean leader Kim Jong Il to help secure their release.
August 5, 2009 - The women are pardoned and released after 140 days in captivity.
May 18, 2010 - Laura Ling and sister Lisa Ling's book, "Somewhere Inside: One Sister's Captivity in North Korea and the Other's Fight to Bring Her Home", is published.
September 28, 2010 - Release date for Euna Lee's book, "The World Is Bigger Now: An American Journalist's Release from Captivity in North Korea . . . A Remarkable Story of Faith, Family, and Forgiveness".
Merrill Newman October 26, 2013 - Merrill Newman of Palo Alto, California, is detained in North Korea, according to his family. Just minutes before his plane is to depart, Newman is removed from the flight by North Korean authorities, his family says.
November 22, 2013 - The U.S. State Department says North Korea has confirmed to Swedish diplomats that it is holding an American citizen. The State Department has declined to confirm the identity of the citizen, citing privacy issues, but the family of Merrill Newman says the Korean War veteran and retired financial consultant has been detained since October.
November 30, 2013 - The Korean Central News Agency (KCNA) reports Merrill issued an apoploy to the people of North Korea, "After I killed so many civilians and (North Korean) soldiers and destroyed strategic objects in the DPRK during the Korean War, I committed indelible offensive acts against the DPRK government and Korean people." His statement ends: "If I go back to (the) USA, I will tell the true features of the DPRK and the life the Korean people are leading."
Eddie Yong Su Jun April 12, 2011 - An American man has been detained by North Korean authorities, State Department officials tell CNN. A diplomatic source familiar with the case says the man entered North Korea in November.
April 14, 2011 - The KCNA reports that U.S. citizen Eddie Yong Su Jun was arrested in November 2010 and has been under investigation for committing a crime against North Korea. No details are provided on the alleged crime.
April 2011 - North Korean says Yong Su Jun has admitted his crime. The specific nature of the crime has not been revealed.
May 27, 2011 - Following a visit from the American delegation which includes the special envoy for North Korean human rights, Robert King, and the Deputy Assistant Administrator of the US Agency for International Development, Jon Brause, to North Korea, detainee Eddie Yong Su Jun is released.
Timothy Hallett Tracy April 24, 2013 - Timothy Hallett Tracy, of Los Angeles, is arrested at the Caracas airport, according to Reporters Without Borders. Tracy traveled to Venezuela to make a documentary about the political division gripping the country.
April 25, 2013 - In a televised address, newly elected President Nicolas Maduro, successor to the late Hugo Chavez, says he ordered the arrest of Tracy for "financing violent groups."
April 26, 2013 - State Dept. spokesman Patrick Ventrell confirms the arrest of an American in Caracas but declines to comment on the specifics of the case. He says the accusations are the latest in a series of allegations in recent weeks made by the Venezuelan government that "foreign actors" are attempting to influence political developments in the country.
April 27, 2013 - Timothy Hallett Tracy is formally charged with conspiracy, association for criminal purposes and use of a false document.
June 5, 2013 - Tracy is released from prison and expelled from Venezuela.