Here's a look at Yemen, a country located on the southwestern tip of the Arabian Peninsula, sharing a border with Saudi Arabia and Oman.
(from the CIA World Fact Book)
Area: 527,968 sq km (twice the size of Wyoming)
Abdu Rabu Mansour Hadi
al Qaeda in the Arabian Peninsula
Ali Abdullah Saleh
Middle East and North Africa
Unmanned military aircraft
Unrest, conflicts and war
Aviation and aerospace industry
Business and industry sectors
Government and public administration
International relations and national security
Political Figures - Intl
Terrorism and counter-terrorism
Business, economy and trade
Population and demographics
Embassies and consulates
Government bodies and offices
State departments and diplomatic services
Continents and regions
Government departments and authorities
Government organizations - Intl
Health and medical
Weapons and arms
Deaths and fatalities
Population: 28,667,230 (July 2018 est.)
Median age: 19.8 years
Ethnic groups: Predominantly Arab, also Afro-Arab, South Asian and European
GDP (purchasing power parity): $73.63 billion (2017 est.)
GDP per capita: $2,500 (2017 est.)
Unemployment: 27% (2014 est.)
Yemen is part of the Arab League.
Since 2004, a group of militant Shiite Muslims called the Houthis have been rebelling against the Yemeni government. The conflict is both separatist and sectarian. Houthis are from northern Yemen and they are Shiite Muslims in a majority Sunni country. Some Western diplomats have said the Houthi rebellion is supported by Iran while Yemen's government has alleged that the Houthis are backed by Hezbollah, the Lebanese Shiite militia. In December 2017, US Ambassador to the United Nations Nikki Haley presented evidence that a missile fired by Houthis at a civilian target was supplied by Iran.
May 22, 1990 - The Republic of Yemen is created from the unification of North Yemen, the Yemen Arab Republic and South Yemen, the People's Democratic Republic of Yemen.
May-July 1994 - A civil war between northerners and southerners begins due to disagreements between supporters of President Ali Abdullah Saleh, from North Yemen, and Vice President Ali Salim al-Baid, from South Yemen. Troops loyal to President Saleh win the war.
September 25, 1999 - Saleh wins the country's first direct presidential election, with 96.3% of the vote. Opposition leaders allege tampering at the ballot box.
September 23, 2006 - Saleh wins re-election to a seven-year term with 77% of the vote.
December 28, 2009 - A Yemen-based arm of al Qaeda, al Qaeda in the Arabian Peninsula (AQAP), claims responsibility for a failed bombing on a Northwest Airlines flight from Amsterdam to Detroit on December 25.
January 2, 2010 - US President Barack Obama announces a new counterterrorism partnership with Yemen, involving intelligence sharing, military training and joint attacks.
January 3, 2010 - The United States and the United Kingdom temporarily close their embassies in Sanaa after they receive word that AQAP may be planning an attack on the facilities. The US embassy reopens two days later after Yemeni forces kill two AQAP militants in a counterterrorism operation.
January 2010 - A group called Friends of Yemen is established in the United Kingdom to rally support for Yemen from the international community. They later hold meetings in London and Saudi Arabia.
January 27, 2011 - Protests break out, inspired by demonstrations in neighboring countries. The unrest continues for months, while crackdowns on protesters lead to civilian deaths.
June 3, 2011 - Opposition forces launch missiles at the presidential palace, injuring Saleh and killing several others.
September 23, 2011 - Saleh returns to Yemen after more than three months of medical treatment in Saudi Arabia.
November 23, 2011 - Saleh signs an agreement in Saudi Arabia transferring his executive powers to Abdu Rabu Mansour Hadi, Yemen's vice president, effectively ending his rule.
January 21, 2012 - Parliament approves a law that grants Saleh immunity from prosecution.
February 21, 2012 - Yemen holds presidential elections to replace Saleh. There is only one candidate on the ballot, Vice President Hadi, the acting president since November 2011. Hadi receives 99.8% of the 6.6 million votes cast, according to the government elections committee.
February 25, 2012 - Hadi is sworn in as president.
May 23, 2012 - The Friends of Yemen group pledges more than $4 billion in aid to help the country fight terrorism and boost its economy. The amount is later increased to $7.9 billion. There are delays, however, that hold up delivery of the funds, according to Reuters.
December 5, 2013 - Militants attack a Defense Ministry hospital in Sanaa. They ram the building with an explosives-laden vehicle and gunmen battle security forces inside. At least 52 people are killed, including four foreign doctors, according to the government.
December 15, 2013 - Parliament calls for an end to drone strikes on its territory three days after a US missile attack mistakenly hits a wedding convoy, killing 14 civilians.
February 10, 2014 - State news reports that Hadi has approved making Yemen a federal state consisting of six regions: two in the south, and four in the north. Sanaa is designated as neutral territory.
September 21, 2014 - Hadi, Houthi rebels and representatives of major political parties sign a ceasefire deal. The United Nations-brokered deal ends a month of protests by Houthis that essentially halted life in Sanaa and resulted in hundreds of people being killed or injured.
January 17, 2015 - Houthi rebels kidnap Hadi's Chief of Staff Ahmed bin Mubarak in a push for more political power. He is released 10 days later, according to Reuters.
January 20, 2015 - Houthi rebels take over the presidential palace.
January 22, 2015 - President Hadi resigns shortly after the prime minister and the cabinet step down. Houthis say they will withdraw their fighters from Sanaa if the government agrees to constitutional changes including fair representation for marginalized groups within the country. No agreement is reached.
February 11, 2015 - The United States and the United Kingdom suspend embassy operations in Yemen.
March 22, 2015 - Houthi rebels seize the international airport in Taiz.
December 6, 2015 - The governor of the city of Aden and six bodyguards are killed in a car bombing. ISIS claims responsibility.
April-August 2016 - Direct peace talks between the warring parties take place in Kuwait, but fail after Houthi rebels reject a UN proposal aimed at ending the war. Yemeni government officials leave the discussions shortly afterward.
November 28, 2016 - The Iranian-backed Houthi movement forms a new government in the capital. Abdul Aziz Habtoor, who defected from Hadi's government and joined the Houthi coalition in 2015, is its leader, according to the movement's news agency Saba.
December 18, 2016 - A suicide bomber strikes as soldiers line up to receive their salaries at the Al Solban military base in the southern city of Aden. The strike kills at least 52 soldiers and injures 34 others, two Yemeni senior security officials tell CNN. ISIS claims responsibility.
January 29, 2017 - US Central Command announces that a Navy SEAL was killed during a raid on a suspected al Qaeda hideout in a Yemeni village. The Navy SEAL is later identified as William Owens. The Pentagon reports that 14 terrorists were killed during the raid. Yemeni officials say civilians got caught in the crossfire and 13 people died, including eight-year-old Nawar Anwar Al-Awalki, the daughter of Anwar Al-Awalki. The raid was authorized by US President Donald Trump, days after he was sworn in as commander in chief.
October 16, 2017 - US forces conduct airstrikes against two ISIS training camps in what a defense official tells CNN are the first US strikes specifically targeting ISIS in Yemen.
November 4, 2017 - Houthi rebels fire a missile at the King Khalid International Airport in Riyadh. The Saudi government says that their military intercepted the missile before it reached its target. The Saudis carry out airstrikes on Sanaa in response.
November 6, 2017 - Saudi Arabia blocks humanitarian aid planes from landing in Yemen. The move is in retaliation for the attempted missile strike on Riyadh
December 4, 2017 - Saleh is killed by Houthi rebels as he tries to flee Sanaa.
December 21, 2017 - The International Committee of the Red Cross announces that one million cases of cholera have been reported in Yemen since the outbreak began during the spring. More than 2,200 people have died, according to the World Health Organization. It is the largest outbreak of the disease in recent history.
April 3, 2018 - Speaking at a UN Pledging Conference on Yemen, UN Secretary General Antonio Guterres notes that, in its fourth year of conflict, more than three-quarters of the population, 22 million, require humanitarian aid. Regarding hunger alone, "some 18 million people are food insecure; one million more than when we convened last year."
August 3, 2018 - The World Health Organizations warns that Yemen is teetering on the brink of a third cholera epidemic.
August 9, 2018 - A Saudi-led coalition bombs a school bus killing 40 boys returning from a day trip in the northern Saada governorate. Fifty-one people are killed in total. Later, munitions experts tell CNN that the bomb, a 500-pound (227 kilogram) laser-guided MK 82 bomb made by Lockheed Martin, was sold as part of a US State Department-sanctioned arms deal with Saudi Arabia. The Saudi coalition blames "incorrect information" for the strike, admits it was a mistake and takes responsibility.
November 20, 2018 - Save the Children says that an estimated 85,000 children under the age of 5 may have died from extreme hunger or disease since the war in Yemen escalated in early 2015.
December 6, 2018 - The opposing sides in Yemen's conflict begin direct talks in Sweden, the first direct discussions between the parties since 2016.