I translated 500.000 U.S dollars, to about 426.000. That's a lot of money, but let's pretend that it's straight up 500.000.
I would do the following:
1. I would buy my dad's countryside house, and finish renovating it.
2. Buy my grandmother's summer cabin/lakeside property in rural eastern Finland.
3. Buy a nice car
. Not a supercar or anything, but something nicer than what I have now.
4. Probably quit my job, or work very little. At the same time I would apply to a university. Start some new hobbies, maybe write a book?
5. Deposit some money to my sister, mother, and father.
By my calculations, I would still have over 100K at this point. I'll save that for any unforeseen expenses that might occur in the future.