2015 Jan 3 to 7 Boko Haram massacres in Nigeria
A series of massacres in Baga, Nigeria and surrounding villages by Boko Haram kill more than 2,000 people.

2015 January 7 Charlie Hebdo cartoonists killed
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.

2015 March 6 NASA probe visits dwarf planet
NASA's Dawn probe enters orbit around Ceres, becoming the first spacecraft to visit a dwarf planet

2015 May 21 Palmyra taken
The ancient city of Palmyra in Syria, famous for its remains of classical architecture, is captured by the Islamic State (ISIS)

2015 June 30 Cuba eradicates transmission of HIV to children
Cuba becomes the first country in the world to eradicate mother-to-child transmission of HIV and syphilis

2015 July 14 Pluto visited for the first time
NASA's New Horizons spacecraft performs a close flyby of Pluto, becoming the first spacecraft in history to visit the distant world.

2015 July 14 Iran nuclear deal agreed
Iran agrees to long-term limits of its nuclear program in exchange for sanctions relief

2015 September 10 Unknown early human discovered in South Africa
Scientists announce the discovery in South Africa of Homo naledi, a previously unknown species of early human

2015 September 11 Queen Elizabeth II becomes longest-reigning British monarch
Queen Elizabeth II, having been on the throne for 63 years, 217 days, becomes the longest-reigning British monarch, surpassing the reign of Queen Victoria

2015 September 14 Gravitational waves detected
Gravitational waves are detected for the first time, by LIGO

2015 September 18 VW diesel tests in question
Automaker Volkswagen is alleged to have been involved in worldwide rigging of diesel emissions tests, affecting an estimated 11 million vehicles globally

2015 September 24 Hajj stampede kills thousands
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

2015 September 28 Water found on Mars
NASA announces that liquid water has been found on Mars

2015 October 23 Strongest hurricane ever in the Western Hemisphere
Hurricane Patricia becomes the most intense hurricane ever recorded in the Western Hemisphere with winds of 215 mph

2015 November 24 Russian fighter shot down by Turkey
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

2015 December 12 COP21 Climate agreement in Paris
A global climate change pact is agreed at the COP 21 summit, committing all countries for the first time to reduce carbon emissions 

2015 December 22 First reusable rocket
SpaceX lands an unmanned Falcon 9 rocket, the first reusable rocket to successfully enter orbital space and return