2015

January

 * January 1
 * The Eurasian Economic Union comes into effect, creating a political and economic union between Russia, Belarus, Armenia, Kazakhstan and Kyrgyzstan.
 * Lithuania officially adopts the euro as its currency, replacing the litas, and becomes the nineteenth Eurozone country.
 * January 3–7 – A series of massacres in Baga, Nigeria and surrounding villages by Boko Haram kills more than 2,000 people.
 * January 7 – Two gunmen belonging to Al-Qaeda's Yemen branch kill 12 people and injure 11 more at the Paris headquarters of satirical newspaper Charlie Hebdo, prompting an anti-terrorism demonstration attended by over a million people and more than 40 world leaders.
 * January 12 – Government raids kill 143 Boko Haram fighters in Kolofata, Cameroon.
 * January 15 – The Swiss National Bank abandons the cap on the franc's value relative to the euro, causing turmoil in international financial markets.
 * January 19 – The Eritrean Catholic Church is founded.
 * January 22 – After Houthi forces seize the presidential palace, Yemeni President Abd Rabbuh Mansur Hadi resigns after months of unrest.

February

 * February 12
 * Leaders from Russia, Ukraine, Germany and France reach an agreement on the conflict in eastern Ukraine that includes a ceasefire and withdrawal of heavy weapons. However, several days later, the Ukrainian government and pro-Russian rebels claim that, within its first day, the ceasefire was broken 139 times, as both sides failed to withdraw their heavy weapons and fighting had continued.
 * The United Nations Security Council adopts Resolution 2199 to combat terrorism.
 * February 14 – Two people were killed and five policemen wounded in Copenhagen, Denmark, at a shooting at Krudtønden cultural centre and the Great Synagogue.
 * February 16 – The Egyptian military begins conducting airstrikes against a branch of the Islamic militant group ISIL in Libya in retaliation for the group's beheading of over a dozen Egyptian Christians.

March

 * March 5–8 – The ancient city sites of Nimrud, Hatra and Dur-Sharrukin in Iraq are demolished by the Islamic State of Iraq and the Levant.
 * March 6 – NASA's Dawn probe enters orbit around Ceres, becoming the first spacecraft to visit a dwarf planet.
 * March 12 – The Islamic State of Iraq and the Levant becomes allies with fellow jihadist group Boko Haram, effectively annexing the group.
 * March 24 – An Airbus A320-211 operated by Germanwings crashes in the French Alps, killing all 150 on board.
 * March 25 – A Saudi Arabia-led coalition of Arab countries starts a military intervention in Yemen in order to uphold the Yemeni government in its fight against the Houthis' southern offensive.

April

 * April 2 – 148 people are killed, the majority students, in a mass shooting at the Garissa University College in Kenya, perpetrated by the militant terrorist organization Al-Shabaab.
 * April 25 – A magnitude 7.8 earthquake strikes Nepal and causes 8,857 deaths in Nepal, 130 in India, 27 in China and 4 in Bangladesh with a total of 9,018 deaths.
 * April 29 – The World Health Organization (WHO) declares that rubella has been eradicated from the Americas.

May

 * May 1 – October 31 – Expo 2015 is held in Milan, Italy.
 * May 7 – the 2015 UK General Election results in the first Conservative majority government in 18 years.
 * May 11–12 – Version O of Les Femmes d'Alger by Pablo Picasso sells for US$179.3 million at Christie's auction in New York, while the sculpture L'Homme au doigt by Alberto Giacometti sells for US$141.3 million, setting a new world record for a painting and for a sculpture, respectively.
 * May 12 – A second major earthquake in Nepal, measuring 7.3 on the moment magnitude scale, results in 153 deaths in Nepal, 62 in India, 1 in China and 2 in Bangladesh with a total of 218 deaths.
 * May 20 – The two constituent republics of Novorossiya, the Donetsk People's Republic and the Luhansk People's Republic, announce the suspension of the Novorossiya project, returning to separate (though internationally unrecognised) states.
 * May 21 – ISIS captures the ancient city of Palmyra in Syria.
 * May 23 – Ireland votes to legalize same-sex marriage, becoming the first country to legalize same-sex marriage by popular vote.

June

 * June 2 – FIFA President Sepp Blatter announces his intention to resign amidst an FBI-led corruption investigation, and calls for an extraordinary congress to elect a new president as soon as possible.
 * June 6 – The governments of India and Bangladesh officially ratify their 1974 agreement to exchange enclaves along their border.
 * June 25–26 – ISIL claim responsibility for three attacks around the world during Ramadan:
 * Kobanî massacre: ISIL fighters detonate three car bombs, enter Kobanî, Syria, and open fire at civilians, killing more than 220.
 * Sousse attacks: 22-year-old Seifeddine Rezgui opens fire at a tourist resort at Port El Kantaoui, Tunisia, killing 38 people.
 * Kuwait mosque bombing: A suicide bomber attacks the Shia Mosque Imam Ja'far as-Sadiq at Kuwait City, Kuwait, killing 27 people and injuring 227 others.


 * June 30 – Cuba becomes the first country in the world to eradicate mother-to-child transmission of HIV and syphilis.

July

 * July 1 – Greek government-debt crisis: Greece becomes the first advanced economy to miss a payment to the International Monetary Fund in the 71-year history of the IMF.
 * July 5–13 – Greek government-debt crisis: After six months of clashes and futile negotiations between Greece's newly elected, leftist government and the country's creditors, over the austerity measures imposed through bailout programmes, tension peaks as Greece votes in a referendum to reject the terms offered in a third programme; however the government eventually proceeds to concur to harsher terms than those offered before, in what was widely characterized as a coup on the creditors' part.
 * July 14
 * NASA's New Horizons spacecraft performs a close flyby of Pluto, becoming the first spacecraft in history to visit the distant world.
 * Iran agrees to long-term limits of its nuclear program in exchange for sanctions relief.
 * July 20 – Cuba and the United States reestablish full diplomatic relations, ending a 54-year stretch of hostility between the nations.
 * July 24 – Turkey begins a series of airstrikes against PKK and ISIL targets after the 2015 Suruç bombing.

August

 * August 5 – Debris found on Réunion Island is confirmed to be that of Malaysia Airlines Flight 370, missing since March 2014.
 * August 17 – A bombing takes place inside the Erawan Shrine at the Ratchaprasong intersection in Pathum Wan District, Bangkok, Thailand, killing 20 people and injuring 125.

September

 * September 10 – Scientists announce the discovery of Homo naledi, a previously unknown species of early human in South Africa.
 * September 11 – Queen Elizabeth II, having been on the throne for 63 years, 232 days, became the longest-reigning British monarch in history and the longest-serving head of state of any nation in modern history, surpassing Queen Victoria who had reigned for 63 years, 231 days upon her death on January 22, 1901.
 * September 14
 * First observation of gravitational waves: Gravitational waves are detected for the first time, by LIGO. This is not announced until February 11, 2016.
 * Malcolm Turnbull defeats Tony Abbott in a Liberal Party leadership ballot. Turnbull becomes Prime Minister of Australia, being sworn in the following day.
 * September 18 – Automaker Volkswagen is alleged to have been involved in worldwide rigging of diesel emissions tests, affecting an estimated 11 million vehicles globally.
 * September 24 – A stampede during the Hajj pilgrimage in Mecca kills at least 2,200 people and injures more than 900 others, with more than 650 missing.
 * September 28 – NASA announces that liquid water has been found on Mars.
 * September 30 – Russia begins air strikes against ISIL and anti-government forces in Syria, in support of the Syrian government.

October

 * October 3 – A United States airstrike on a Médecins Sans Frontières (Doctors Without Borders) hospital in Afghanistan accidentally kills an estimated 20 people.
 * October 10 – A series of suicide bombings kills at least 100 people at a peace rally in Ankara, Turkey, and injures more than 400 others.
 * October 23 – Hurricane Patricia becomes the most intense hurricane ever recorded in the Western Hemisphere and the second strongest worldwide, with winds of 215 mph and a pressure of 872 mbar.
 * October 26 – A magnitude 7.5 earthquake strikes the Hindu Kush region and causes 398 deaths, with 279 in Pakistan, 115 in Afghanistan and 4 in India.
 * October 31 – Kogalymavia Flight 9268, an Airbus A321 airliner en route to Saint Petersburg from Sharm el-Sheikh, crashes near Al-Hasana in Sinai, killing all 217 passengers and 7 crew members on board.

November

 * November 7 – CPC general secretary Xi Jinping and ROC president Ma Ying-jeou formally meet for the first time.
 * November 12 – Two suicide bombers detonated explosives in Bourj el-Barajneh, Beirut, killing 43 people and injuring over 200 others.
 * November 13 – Multiple terrorist attacks claimed by Islamic State of Iraq and the Levant (ISIL) in Paris, France, result in 130 fatalities.
 * November 24 – Turkey shoots down a Russian fighter jet on the Turkish-Syrian border in the first case of a NATO member destroying a Russian aircraft since the 1950s.
 * November 30 – The 2015 United Nations Climate Change Conference (COP 21) is held in Paris, attended by leaders from 147 nations.

December

 * December 2 – Two gunmen open fire at a workplace in San Bernardino, California killing 14 before dying themselves in a shootout with police. Islamic State of Iraq and the Levant claimed responsibility.
 * December 12 – A global climate change pact is agreed at the COP 21 summit, committing all countries to reduce carbon emissions for the first time.
 * December 15 – The Islamic Military Alliance is formed in order to fight terrorism.
 * December 22 – SpaceX lands an unmanned Falcon 9 rocket, the first reusable rocket to successfully enter orbital space and return.