I advice you to invest it in the gambling site because most of the users were starting to become addict in gambling. Also due to high price of Bitcoin in the market the users were starting to trust their luck to easy earn income.
Yes nowadays when they see the price increasing they become more eager to earn bitcoin faster and for that they often go to casino to play a bet and to win a big amount within a few minutes so if he will invest them in a trusted casino then he will earn a profit with that.
Besides this if any person have that much bitcoin now then they can easily start their own small factory with that especially in the developing countries it is possible to start with that money.