A newly released World Anti-Doping Agency (WADA) report says Russia operated a state-sponsored doping programme for four years across most sports at both the summer and winter Olympics.
The McLaren report claims Russia's sports ministry manipulated its athlete's urine samples by collecting the real samples and replacing them with clean urine that had been frozen and stored in special banks.
In other cases, Russian samples that had tested positive would simply 'go missing'.
The report says Russia's doping programme started in late 2011, and was in place for the London Olympics in 2012 and the Sochi Winter Olympics in 2014.
After a poor showing by Russian athletes at the 2010 Winter Olympics in Vancouver, the pressure was on to win many more at the Sochi Games in 2014 - and the state-sponsored doping programme reached its zenith.
The cheaters created an intricate system using clean, frozen urine, a secret 'mouse hole' in the testing laboratory to pass it through, and special agents disguised as sewer workers to collect it.
Russia won only 15 medals in Vancouver, but topped the medal count in Sochi with 33, including 13 gold.
Reaction has been swift with the International Olympic Committee (IOC) president Thomas Bach calling the findings a: "shocking and unprecedented attack on the integrity of sport and on the Olympic Games" and pledged to enforce "the toughest sanctions available".
The New Zealand Olympic Committee (NZOC) released a statement early this morning saying the findings were: "shocking and deeply concerning" and that its thoughts are "with the clean athletes around the world that have been negatively impacted by the long-term systematic cheating."
Lord Coe, president of the International Association of Athletics Federations (IAAF), essentially said 'told you so': "The institutionalised and systematic doping in Russian athletics is the reason the IAAF suspended, and then upheld the suspension of Russia Athletics Federation's membership."
The McLaren report has had a mixed response in Russia.
Gazeta.ru said it could mark the start of: "the most difficult week in the history of Russian sport", while the country's most popular sports website Championat.ru claimed the McLaren report was part of a co-ordinated anti-Russian plot.
It's likely all of Russia's medal-winners will now have their titles stripped from the London and Sochi Olympics.
At present, Russia's track and field athletes are barred from competing in Rio by the IAAF, but the All-Russia Athletic Federation (ARAF) has appealed the ban to the Court of Arbitration for Sport.
If that appeal fails a small number of Russian athletes will probably still compete in Rio providing they can prove they are clean, but they'll have to compete under the Olympic flag, not Russia's.
Newshub.
