Best bet would be to use half of it as down payment for as many houses/apartments that you can get with a buy-to-let mortgage. If you don't want to deal with all the hassle of being a landlord, neither with the potential trouble you could have with any number of your tenants, just put it into a solid index fund and call it a day. Average 10-15% annual return; recently much more. Worst case scenario, say it's 5% annually long term. Pretty liquid too anyway, so you could easily move it between that, bonds and a savings account depending on their returns at any given time.
The most important step would be moving to a very cheap country to live in, with nice weather and good food, low crime rate, etc. Have fun
