Bradley Manning, a 25-year-old US private, downloaded more than 700,000 classified documents from US military servers and passed them to WikiLeaks. The Guardian was one of several news organisations to publish a series of stories based on the contents of the files. Below are 10 of the most revelatory:

• The first revelation came in 2010, from a video showing a US helicopter crew laughing as they launched an air strike killing a dozen people in Baghdad in July 2007, including a photographer and driver working for the Reuters news agency. The footage was recorded on one of two Apache helicopters which were hunting for suspected insurgents. They encounter a group of men on the ground, who do not immediately appear armed, and there is no sign of gunshots. But one helicopter crew opens fire, with shouts of "Hahaha. I hit 'em," and "Oh yeah, look at those dead bastards". As the wounded are helped, one of the helicopters opens fire again, with armour-piercing shells.

• The next tranche of revelations came in July 2010, from documents dating from 2004 to 2009 about the Afghan war. One set raised concerns in the US by suggesting alleged support for the Taliban from Pakistan, particularly that the country's spy agency, the Inter-Services Intelligence (ISI), had been collaborating with the Taliban.

• The Afghanistan files also included details of an incident from 2007 in which US marines escaping an attack outside the city of Jalalabad fired their guns indiscriminately, killing 19 unarmed civilians and wounding 50 more. While the aftermath of the attack was plain to military authorities, the files suggested, the incident was referred to in an official report only as this: "The patrol returned to JAF [Jalalabad air field]."

• In October 2010 came a series of revelations about events in Iraq. Chief among these was that US authorities failed to investigate hundreds of reports of abuse, torture, rape and even murder by Iraqi police and soldiers. The reports of abuse, often supported by medical evidence, describe prisoners shackled, blindfolded and hung by wrists or ankles, and subjected to whipping, punching, kicking or electric shocks.

• Another Iraq-related revelation was that the US collated details of more than 100,000 people killed in Iraq following the invasion of the country, including more than 15,000 deaths that were previously unrecorded. The tally goes against previous protestations by the UK and US that there were any official statistics on the death toll connected to the war.

• The largest and most explosive cache of files was revealed in November 2010 – more than 250,000 classified cables from US embassies, carrying confidential and often blunt diplomatic assessments of US allies and foes. One of the most dramatic of these showed that King Abdullah of Saudi Arabia has repeatedly urged the US to attack Iran to destroy its nuclear programme. The Saudi monarch was recorded as having "frequently exhorted the US to attack Iran to put an end to its nuclear weapons programme," one cable stated.

• The embassy cables also said that the US is running a secret intelligence campaign targeted at the leadership of the United Nations, including the secretary general, Ban Ki-moon, and representatives from China, Russia, France and the UK. The classified directive, from 2009, demanded details about the communications systems used by top UN officials, including passwords and personal encryption keys used in official communications.

• Other cables painted a hugely unflattering US view of Russia under the leadership of Vladimir Putin, calling it a "virtual mafia state" in which officials, oligarchs and organised crime are bound together by endemic corruption and personal enrichment.

• The cables contained an equally candid view of rampant government corruption in Afghanistan, including details of an incident in October 2009 when the then vice-president, Ahmad Zia Massoud, was stopped and questioned in Dubai carrying $52m in cash.

• On a more intimate note, but of particular interest in Britain, was a cable from Tatiana Gfoeller, Washington's ambassador to Kyrgyzstan, who recounted an "astonishingly candid" and at times rude performance by Prince Andrew at a brunch with overseas business people in which he railed against British anticorruption investigators, journalists and the French.

• The final tranche of revelations, in April 2011, came from 759 "detainee assessment" dossiers about those held at the Guantánamo Bay prison, written between 2002 and 2009. They spell out the extent of involvement US authorities believe each detainee has had with al-Qaida, the Taliban or other terror groups. The files showed that some prisoners had long ago been cleared for release but remained detained.