Bitconnect scam!
For months prior to the shutdown of Bitconnect, it was one of the popular lending and exchange platform in the Crypto world. However, people have been suspecting that the platform itself is running a Ponzi Scheme.
January this year, after two cease and desist orders , Bitconnect finally shutdown promising to refund their users. However with the Bitconnect token crashing down $200+ to ~$37 by January, a lot of people lost their money. I personally think it is the biggest scam in the history of the Crypto world.