To double it safely i will build a food business which most people really like.
I'll build a restaurant spending all $100k. Although doubling it will require some time but
it will be safe in that way. Rather than investing it on some networking or use it as trading capital
which have a high risk of doubling money.
And one more thing is to invest it to bitcoin then after few years get it back to your wallet and spend it, since then it is increasing great high now, no losing chance so far with that.