WikiLeaks has been making headlines for more than a decade by releasing millions of classified documents, embarrassing governments while also raising fears that its activities may have put lives in danger.
Controversy also swirls around its founder Julian Assange, who was arrested on Thursday after being holed up in the Ecuadoran embassy in London for nearly seven years.
Here are five things to know about WikiLeaks.
- 10 million leaks -
WikiLeaks was founded in 2006 by Australian-born Assange, who said it would use encryption and a censorship-proof website to publish secret information and protect sources.
It first caught the world's attention in 2007 with the release of manuals for US prison guards at Guantanamo Bay.
But it really hit its stride in 2010 when it worked with The New York Times, The Guardian, Der Spiegel, Le Monde and El Pais to publish millions of classified diplomatic cables.
It has published more than 10 million leaked documents and associated analyses, to the dismay of politicians, governments and corporations.
- Controversy strikes -
In its early days, WikiLeaks worked with dissidents worldwide to expose government secrets from the United States to Europe, China, Africa and the Middle East.
But over time it has increasingly set its sights on the US. Assange has denied claims that it might be working with Russia.
WikiLeaks raised a storm in July 2016 by releasing emails showing US Democratic Party officials favouring Hillary Clinton over left-winger Bernie Sanders in the presidential primary elections, forcing high-ranking party members to resign.
WikiLeaks was also accused of revealing the identity of a gay man in ultra-conservative Saudi Arabia. Again, the group denied the accusation.
- Arrest warrant -
The worst scandals to affect WikiLeaks have been those involving Assange.
Hailed as a hero by supporters and reviled as a manipulator by critics, the white-haired Australian was holed up in the Ecuadoran embassy in London since 2012, when he was facing rape allegations in Sweden.
Swedish prosecutors dropped their investigation in 2017 but Assange remained in the embassy, fearing the US would extradite him for revealing state secrets.
- Snowden and Manning -
The mass exposure in 2010 of US diplomatic cables, which embarrassed governments worldwide, would not have been possible had it not been for US soldier Chelsea Manning, who handed WikiLeaks 700,000 classified documents.
She was given a 35-year prison sentence in 2013 and served more than three years before being freed in 2017.
In March 2019 she was jailed again for refusing to testify in a grand jury investigation targeting WikiLeaks.
Former US intelligence contractor Edward Snowden has also received WikiLeaks's backing, though he did not use the group's site to publish his leaks about the National Security Agency.
Assange recommended he quickly flee to Moscow to evade prosecution in the US -- advice he heeded.
- In the movies -
Two major films have been made about WikiLeaks -- "The Fifth Estate" (2013) and "Risk", a documentary that was screened at the Cannes film festival in 2016.
Assange meanwhile guest-starred as himself in an episode of "The Simpsons" in 2012, recording his lines over the phone from the Ecuadoran embassy.