Recently, fascinating allegations of $20.8 billion (yes,
billion) of money laundered from Russia between 2011 and 2014
through a network of 21 shell companies were exposed, and involved
almost every major bank in Europe.
Bank documents released by the Reporters for the Organized Crime
and Corruption Reporting Project (OCCRP) showed a complex money
laundering scheme which involved enormous sums moved from Russia,
through Moldovan and Latvian banks, to 732 banks across 96
countries. The laundered funds were then used to buy luxurious
goods across the world.
How did it work?

For example, a UK company called Seabon Limited filed financial
statements in 2013 showing income of £1. However according to
an analysis of the OCCRP records, Seabon was a shell company,
involved in transactions worth USD $9 billon.