OneCoin was and is a crazy scam.
Nope. The biggest in history, is fractional reserve banking, and its still ongoing. It only takes about 10% for the world population to withdraw their money from banks at the same time to collapse the global economy.
And its legalized. The history of modern banking knows why. Fact is most people are ignorant of this, and because of that, it keeps going.
If you think the Tulips and Mr Ponzi were bad, wait until you actually learn about fractional reserve bank, the way modern banks operate.