January 1 Estonia officially adopts the Euro currency and becomes the seventeenth Euro zone country.
January 4 Tunisian street vendor Mohamed Bouazizi dies after setting himself on fire a month earlier, sparking anti-government protests in Tunisia and later other Arab nations. These protests become known collectively as the Arab Spring.
January 9 -15 - Southern Sudan holds a referendum on independence. The Sudanese electorate votes in favour of independence, paving the way for the creation of the new state in July.
January 11 - Flooding and mudslides in the Brazilian state of Rio de Janeiro kills 903.
January 14 - Arab Spring: The Tunisian government falls after a month of increasingly violent protests; President Zine El Abidine Ben Ali flees to Saudi Arabia after 23 years in power.
January 24 - 37 people are killed and more than 180 others wounded in a bombing at Domodedovo International Airport in Moscow, Russia.
February 11 Arab Spring: Egyptian President Hosni Mubarak resigns after widespread protests calling for his departure, leaving control of Egypt in the hands of the military until a general election can be held.
February 22 - March 14 Uncertainty over Libyan oil output causes crude oil prices to rise 20% over a two-week period following the Arab Spring, causing the 2011 energy crisis.
March 11 A 9.1-magnitude earthquake and subsequent tsunami hit the east of Japan, killing 15,840 and leaving another 3,926 missing. Tsunami warnings are issued in 50 countries and territories. Emergencies are declared at four nuclear power plants affected by the quake.
March 15 Arab Spring: Hamad bin Isa Al Khalifa, King of Bahrain declares a three-month state of emergency as troops from the Gulf Co-operation Council are sent to quell the civil unrest.
March 17 Arab Spring and the 2011 Libyan civil war: The United Nations Security Council votes 10-0 to create a no-fly zone over Libya in response to allegations of government aggression against civilians.
March 19 Arab Spring and the Libyan civil war: In light of continuing attacks on Libyan rebels by forces in support of leader Muammar Gaddafi, military intervention authorized under UNSCR 1973 begins as French fighter jets make reconnaissance flights over Libya.
April 11 Former Ivorian President Laurent Gbagbo is arrested in his home in Abidjan by supporters of elected President Alassane Ouattara with support from French forces thereby ending the 20102011 Ivorian crisis and civil war.
April 29 An estimated two billion people watch the wedding of Prince William, Duke of Cambridge and Catherine Middleton at Westminster Abbey in London.
May 1 U.S. President Barack Obama announces that Osama bin Laden, the founder and leader of the militant group Al-Qaeda, has been killed during an American military operation in Pakistan.
May 16 The European Union agree to 78 billion rescue deal for Portugal. The bailout loan will be equally split between the European Financial Stabilisation Mechanism, the European Financial Stability Facility, and the International Monetary Fund.
May 26 Former Bosnian Serb Army commander Ratko Mladi?, wanted for genocide, war crimes and crimes against humanity, is arrested in Serbia.
June 4 Chile's Puyehue volcano erupts, causing air traffic cancellations across South America, New Zealand, Australia and forcing over 3,000 people to evacuate.
June 5 Arab Spring: Yemeni President Ali Abdullah Saleh travels to Saudi Arabia for treatment of an injury sustained during an attack on the presidential palace. Protesters celebrate his transfer of power to his Vice-President Abd al-Rab Mansur al-Hadi.
June 12 Arab Spring: Thousands of Syrians flee to Turkey as Syrian troops lay siege to Jisr ash-Shugur.
July 7 The world's first artificial organ transplant is achieved, using an artificial windpipe coated with stem cells.
July 9 South Sudan secedes from Sudan, per the result of the independence referendum held in January.
July 20 Goran Hadi? is detained in Serbia, becoming the last of 161 people indicted by the International Criminal Tribunal for the former Yugoslavia.The United Nations declares a famine in southern Somalia, the first in over thirty years.
July 21 Space Shuttle Atlantis lands successfully at Kennedy Space Center after completing STS-135, concluding NASA's space shuttle program.
July 22 76 people are killed in twin terrorist attacks in Norway after a bombing in the Regjeringskvartalet government center in Oslo and a shooting at a political youth camp on the island of Utøya.
July 31 In Thailand over 12.8 million people are affected by severe flooding. The World Bank estimates damages at 1,440 billion baht (US$45 billion). Some areas are still six - feet underwater, and many factory areas remained closed, at the end of the year. 790 people are killed, with 58 of the country's 77 provinces affected.
Arab Spring: Because of the uncertaintities associated with a clamp-down of the free press, there are believed to be at least 121 people killed in a Syrian Army tank raid on the town of Hama and over 150 people are reportedly killed across the country.
The total dead throughout Syria may never be known, but an estimate as of September 24 is 3,000.
August 5 NASA announces that its Mars Reconnaissance Orbiter has captured photographic evidence of possible liquid water on Mars during warm seasons.Juno, the first solar-powered spacecraft on a mission to Jupiter, is launched from Cape Canaveral Air Force Station.
August 2028 Arab Spring and the Libyan civil war: In the Battle of Tripoli, Libyan rebels take control the nation's capital, effectively overthrowing the government of Muammar Gaddafi.
September 5 India and Bangladesh sign a pact to end their 40-year border demarcation dispute.
September 10 Zanzibar ferry sinking: The MV Spice Islander I, carrying at least 800 people, sinks off the coast of Zanzibar, killing 240 people.
September 12 Approximately 100 people die after a petrol pipeline explodes in Nairobi.
September 17 Occupy Wall Street protests begin in the United States. This develops into the Occupy movement which spreads to 82 countries by October.
September 19 With 434 dead, the United Nations launches a $357 million appeal for victims of the 2011 Sindh floods in Pakistan.
October 4 2011 Mogadishu bombing: 100 people are killed in a car bombing in the Somali capital Mogadishu.
The death toll from the flooding of Cambodia's Mekong River and attendant flash floods reaches 207.
October 18 Israel and the Palestinian militant organization Hamas begin a major prisoner swap, in which the captured Israeli Army soldier Gilad Shalit is released by Hamas in exchange for 1,027 Palestinian and Israeli-Arab prisoners held in Israel, including 280 prisoners serving life sentences for planning and perpetrating terror attacks.
Arab Spring and the Libyan civil war: Libyan leader Muammar Gaddafi is killed in Sirte, with National Transitional Council forces taking control of the city, and ending the war.
Basque separatist militant organisation ETA declares an end to its 43-year campaign of political violence, which has killed over 800 people since 1968.
October 23 A magnitude 7.2 Mw earthquake jolted eastern Turkey near the city of Van, killing 604 people, and damaging about 2,200 buildings.
October 27 After an emergency meeting in Brussels, the European Union announced an agreement to tackle the European sovereign debt crisis which includes a writedown of 50% of Greek bonds, a recapitalisation of European banks and an increase of the bailout fund of the European Financial Stability Facility totaling to 1 trillion.
October 31 Date selected by the UN as the symbolic date when global population reaches seven billion.
UNESCO admitted Palestine as a member, following a vote in which 107 member states supported and 14 opposed.
November 26 The Mars Science Laboratory rover Curiosity, the most elaborate Martian exploration vehicle to date, is launched from the Kennedy Space Center. It is slated to land on Mars on August 5, 2012.
December 15 The United States formally declares an end to the Iraq War.
December 16 Tropical Storm Washi causes 1,257 flash flood fatalities in the Philippines with 85 people officially listed as missing.
December 29 Samoa and Tokelau move from east to west of the International Date Line, thereby skipping December 30, in order to align their time zones better with their main trading partners.