On Sunday the world became familiar with the Panama Papers: a massive 2.6-terabyte leak of confidential documents revealing a deep web of international corruption and tax evasion from the world's political elite.

Panamanian law firm Mossack Fonseca — which specializes in helping foreigners set up international shell companies to protect their financial assets – leaked the papers to the International Consortium of Investigative Journalists to expose the offshore holdings and hidden financial dealings of some of the world's most familiar names.

Vox's Matt Yglesias explains:

The documents provide details on some shocking acts of corruption in Russia, hint at scandalous goings-on in a range of developing nations, and may prompt a political crisis in Iceland. But they also offer the most granular look ever at a banal reality that's long been hiding in plain sight. Even as the world's wealthiest and most powerful nations have engaged in increasingly complex and intensive efforts at international cooperation to smooth the wheels of global commerce, they have willfully chosen to allow the wealthiest members of Western society to shield their financial assets from taxation (and in many cases divorce or bankruptcy settlement) by taking advantage of shell companies and tax havens.

More than 100 media organizations spent a year poring over 11.5 million leaked files with 40 years' worth of data connecting more than 214,000 offshore companies to people in 200-plus countries. Here are some key resources to help you catch up on the unfolding scandals.

The Panama Papers is the largest leak of insider information in history. What are some key findings?

1) The Russian government has already said it was "obvious" President Vladimir Putin was the main target of the Panama Papers leak. Whether or not the objective of the leak was to smear the Russian president, the findings showed a $2 billion trail of secret offshore deals and loans all pointing toward Putin.

The Guardian explains the "fabulous fortunes of the Russian president's inner circle":

Though the president’s name does not appear in any of the records, the data reveals a pattern – his friends have earned millions from deals that seemingly could not have been secured without his patronage. The documents suggest Putin’s family has benefited from this money – his friends’ fortunes appear his to spend. [...] Cash was also handed over directly to the Putin circle, this time in the form of very cheap loans, made with no security and with interest rates as low as 1%. It is not clear whether any loans have been repaid.

2) Icelandic Prime Minister Sigmundur Gunnlaugsson walked out of an interview after a Swedish reporter asked him about investments exposed in the Panama Papers.

Gunnlaugsson and his wife, Anna Sigurlaug Pálsdóttir, bought the offshore company Wintris in 2007 to invest millions in Icelandic banks — a line of questioning the prime minister found "totally inappropriate."

The BBC explains Gunnlaugsson's questionable investments:

The leaked documents show that Mr Gunnlaugsson was granted a general power of attorney over Wintris - which gave him the power to manage the company "without any limitation". Ms Palsdottir had a similar power of attorney. Court records show that Wintris had significant investments in the bonds of three major Icelandic banks that collapsed during the financial crisis which began in 2008. Wintris is listed as a creditor with millions of dollars in claims in the banks' bankruptcies. Mr Gunnlaugsson became prime minister in 2013 and has been involved in negotiations about the banks which could affect the value of the bonds held by Wintris.

3) While China’s top leader, Xi Jinping says he is ready to take on the "armies of corruption," the Panama Papers revealed that, like many of the world leaders exposed in this data dump, members of Xi and other top Chinese officials' families are tied to multiple offshore companies.

The papers named Xi's brother-in-law Deng Jiagui and the daughter of former China Premier Li Peng, Li Xiaolin — both names that were previously exposed in a 2014 ICIJ report that the Chinese government denied.

The Washington Post explains why this can create an uncomfortable tension in a country that has tried to wage an aggressive — albeit selective — anti-corruption campaign:

Although there are legal uses for shell companies, the charges are sure to rile Beijing. China’s ruling Communist Party does not like to discuss the wealth of its leaders, or their families, especially as it wages an aggressive, if selective, anti-corruption campaign. [...] In 2014, a report jointly published by the ICIJ and the Center for Public Integrity found 22,000 alleged tax haven clients from Hong Kong and China. That investigation found offshore accounts linked to more than a dozen of China’s richest people, including members of the National People’s Congress and executives from state-owned firms caught up in corruption probes. [...] Asked about the story at a Foreign Ministry press conference that year, a Chinese government spokesperson called the investigation "hardly convincing." The report was subsequently blocked. The Chinese press did not play up the story.

4) It's not only political elites. Top names in the entertainment and athletics industries also made the long list of Mossack Fonseca's clientele. Notably, the list included names closely tied with the already corruption-mired FIFA.

The records showed that four of the 16 FIFA officials indicted in the United States used offshore companies. And then there is famed Argentine player Lionel Messi, who, already under indictment for using offshore companies to skirt taxes, was found to have owned yet another offshore company in Panama: Mega Star Enterprises.

Messi has already said he is ready to sue the Spanish newspaper that outed his record of tax evasion for defamation.

You can read ICIJ's full report on the financial underbelly of international soccer and other athletics here.

The Panama Papers reaffirmed the pervasiveness of tax havens. This has been well documented.

5) The Panama Papers made one thing very clear: Tax havens, meaning countries or independent areas where taxes are levied at a low rate, are ubiquitous. So much so that avoiding them is nearly impossible, Nicholas Shaxson explained in his exposé on the world's tax havens for the Guardian.

"See if you can dodge all my bear traps, and declare yourself untainted by tax havens. If you succeed, you win my Hermit of the Year prize," Shaxson writes of the pervasiveness of these loopholes:

Do you celebrate Christmas? If you do (or even if you do not), did you buy any gifts on Amazon last December? If so, then your goods were quite likely to have been routed through a byzantine world hosted – only on paper, you understand – by the Grand Duchy of Luxembourg, where Amazon has located its European headquarters, slashing its tax bills around the world. In 2011, Amazon revealed that the US Internal Revenue Service was chasing it for $1.5bn in back taxes. More recently, Amazon has said it will stop routing its UK sales through Luxembourg. [...] Let’s cut this challenge short. Did you at any point consume the services of any of these: AIG, Aviva, Barclays, Black & Decker, British American Tobacco, Burberry, Citigroup, Deutsche Bank, Facebook, FedEx, GlaxoSmithKline, Ikea, HSBC, JP Morgan, Microsoft, Pepsi, Skype, Starbucks, Vodafone or Walt Disney? This is just my quirky personal selection from a list of more than 350 multinationals whose convoluted tax schemes were revealed last November by a whistleblower, working for one accountancy firm, PricewaterhouseCoopers (PwC), in one European tax haven, Luxembourg.

6) Tax havens aren't only in Panama and the Cayman Islands. For some, states like Delaware and Wyoming in the United States are tax havens as well.

Bloomberg published "The World’s Favorite New Tax Haven Is the United States." Why? Because even American law firms dedicated to protecting the financial assets of the world's elite say the US is a perfectly effective tax haven:

You can help your clients move their fortunes to the United States, free of taxes and hidden from their governments. Some are calling it the new Switzerland. After years of lambasting other countries for helping rich Americans hide their money offshore, the U.S. is emerging as a leading tax and secrecy haven for rich foreigners. By resisting new global disclosure standards, the U.S. is creating a hot new market, becoming the go-to place to stash foreign wealth. Everyone from London lawyers to Swiss trust companies is getting in on the act, helping the world’s rich move accounts from places like the Bahamas and the British Virgin Islands to Nevada, Wyoming, and South Dakota. "How ironic—no, how perverse—that the USA, which has been so sanctimonious in its condemnation of Swiss banks, has become the banking secrecy jurisdiction du jour," wrote Peter A. Cotorceanu, a lawyer at Anaford AG, a Zurich law firm, in a recent legal journal. "That ‘giant sucking sound’ you hear? It is the sound of money rushing to the USA."

7) But while everyone has heard of the existence of tax havens, the actual practices that go into wealth management are more secretive.

The Atlantic explains how a select few legally "enable their clients to sidestep many laws policies" in its piece "Inside the Secretive World of Tax-Avoidance Experts":

Wealth management is a profession on the defensive. Although many people have never heard of it, it is well known to both state revenue authorities and international agencies seeking to impose the rule of law on high-net-worth individuals. Those individuals—including the 103,000 people classified as "ultra-high-net-worth" based on having $30 million or more in investable assets—pay wealth-management professionals hefty fees to help them avoid taxes, debts, legal judgments, and other obligations the rest of the world considers part of everyday life. The general public doesn’t hear much about these professionals, since there are only a few of them worldwide (just under 20,000 belong to the main professional society) and they strive to keep a low profile, both for themselves and their clients.

Shell companies are the go-to method for the wealthy to protect their assets, because it's really easy.

8) Somewhat surprisingly, it is really easy to set up a shell company. In fact, NPR's podcast Planet Money set up its own shell companies just to test this out: Unbelizeable, Inc., in Belize, and Delawho? in Delaware.

Listen to Planet Money's discoveries on the ins and outs of owning a shell company, and why they are easy to set up and a hassle to deal with.

(The Planet Money team even drafted a resolution that would allow them to go to Belize to meet the "director" and "shareholder" of the company.)