Easy.  The whole run from November through early January this past year.  I got in right at the right time to more than double my money between holding Bitcoin, Ethereum, Litecoin, and XRP.  Managed to cash out at the right time, too.  Unfortunately, I'm pretty sure that I've lost those profits trying to teach myself to trade throughout 2018, but it's an ongoing learning experience.  I have no doubt in Bitcoin and cryptocurrency in the long term.  We just have to have patience.