In total, the ICIJ found links between almost 1,000 companies in offshore havens and 336 high-level politicians and public officials, including more than a dozen serving heads of state and government, country leaders, cabinet ministers, ambassadors and others.
In most countries, the ICIJ stresses, it is not illegal to have assets offshore or to use shell companies to do business across national borders.
But such revelations are no less of an embarrassment for leaders who may have campaigned publicly against tax avoidance and corruption, or advocated austerity measures at home.
Here are some key revelations:
King of Jordan's property empire
The files show King Abdullah II, who has faced angry protests against austerity measures in recent years, created a network of offshore companies and tax havens to amass a $A138 million ($US100 million) property empire between 2003 and 2017, including 15 homes from Malibu, California to Washington and London.
The Jordanian embassy in Washington declined to comment, but the BBC cited lawyers for the king saying all the properties were bought with personal wealth, and that it was common practice for high profile individuals to purchase properties via offshore companies for privacy and security reasons.
Eleven-year-old property owner
Family and associates of Azerbaijani President Ilham Aliyev - long accused of corruption by rights groups - are alleged to have been secretly involved in property deals in Britain worth hundreds of millions, including a roughly $A62 million ($US45 million) office block in the name of the president's 11-year-old son, Heyder.
The central London property was purchased in 2009 by a front company owned by a family friend of the Central Asian state's president before it was transferred to his son, the BBC reported.
Czech premier's chateau looms over election
According to the documents, Czech Prime Minister Andrej Babis failed to declare an offshore investment company used to purchase a chateau worth $A30 million ($22 million) in the south of France.
The premier is facing an election later this week and hit out at the revelations as "trying to tarnish my reputation and affect the Czech general election," saying in an interview with Czech news agency CTK that "it is clear that I didn't do anything illegal or wrong".
Kenyan president's offshore network
The investigation says Kenyan President Uhuru Kenyatta - who has campaigned against corruption and for financial transparency - is accused along with six family members to secretly own a network of 11 offshore companies, one of which was valued as holding assets of $A41 million ($US30 million).
Pakistan premier's inner circle
Members of Pakistan Prime Minister Imran Khan's inner circle, including cabinet ministers and their families, were found to secretly own companies and trusts holding millions of dollars.
Mr Khan himself welcomed the findings on Twitter, saying they exposed "the ill-gotten wealth of elites, accumulated through tax evasion & corruption & laundered out to financial 'havens'" and promised to investigate any wrongdoing.
Links to Russia
While Russian President Vladimir Putin is not directly named in the files, he is linked via associates to secret assets in Monaco - notably a waterfront home acquired by a Russian woman who is believed to have had a child with Putin, The Washington Post reports.
Separately, the documents appear to show that the law firm of President Nicos Anastasiades of Cyprus concealed the identity of the owner of several offshore companies: a former Russian politician accused of embezzlement. The firm denies the accusations, the BBC said.
Ukrainian president's transfer
According to the findings, just before he was elected as Ukraine's president in 2019, Volodymyr Zelensky transferred his stake in a secret offshore company.
Tony Blair's building
Previously an outspoken critic of tax loopholes, former British prime minister Tony Blair and his wife were found to have purchased an $A12 million ($US8.8-million) building in London in 2017 by buying the British Virgin Islands company that owned it.
As per British law, by doing so they avoided paying hundreds of thousands of dollars in taxes.
The BBC noted there was no indication the Blair's were hiding their wealth, and Cherie Blair said the couple had brought the property back under British rules.
Shakira, Schiffer and Tendulkar
Alongside the politicians, the public figures linked to offshore assets also included the Colombian singer Shakira, the German supermodel Claudia Schiffer and the Indian cricket legend Sachin Tendulkar.
Lawyers for all three told the ICIJ the investments were legitimate and denied any suggestion of tax avoidance.
The Pandora Papers are the latest in a series of mass ICIJ leaks of financial documents, from LuxLeaks in 2014, to the 2016 Panama Papers - which triggered the resignation of the prime minister of Iceland and paved the way for the leader of Pakistan to be ousted.
They were followed by the Paradise Papers in 2017 and FinCen files in 2020.
The documents behind the latest investigation are drawn from financial services companies in countries including the British Virgin Islands, Panama, Belize, Cyprus, the United Arab Emirates, Singapore and Switzerland.