Batman?

I could be a billionaire any time. I just need to exchange my savings to Zimbabwean dollars and voilá!

You can actually become a multi-trillionaire for a mere $5 US.

Travel

Even better for me. I'm going to the bank right now, if I wait 5 more minutes the zeros won't fit on the bill.

I'd invest most of my money into an experiment to make me immortal.
After that,well,let's just say i'll try to rule the world.
^_^

20 million for a trip to the moon ? Try Billions .

It depends beeing a low single digit billionaire is not the same as having 50 Billions. It makes a lot of difference in what you can pull of. Having 100 Billion would make me spend 50 on a 2 year trip to Mars. For the rest I would buy 6 Airbus A 380 and put a pool inside one plus style them in different themes so I have one for every mood. Ofcourse eachone would have king size beds kitchens cinemas a garage with 4 selected 250k vehicle. A garden with trees (should work if I cut a hole into the middlefloor. A panorama deck completly out of glass a library . Also I would put in parachutes in case I want to go down somewhere fast. A small fleet of airplanes that fuel the Airbuses in the Air so if Idont feel to land for a week or two I dont have to.

Ofcourse thats not all I would build the freedom ship with an extended length so my airbuses can land on it. I would sell 50% to people around the globe to populate it with 50k humans my part would ofcourse be restricted and only for
selected persons inside the ship I would have 1000 cars jetskis helicopters yards submarines clinics beaches and lakes hotels fast food chains coffee shops (like in amsterdam) restaurants racing circuits yeah that should be enough. That together would be another 40 Billion. Th other 10 Billion plus the Billions I earned from selling all the space on my ship plus the money I earn through millionairs spending in my shops/casinos on my ship would be invested to maintain my ship/planes all profit would go to charity.

I would create millions of jobs and be known forever as biggest spender on earth and first man on mars.

Get rid of all the debt in my entire extended family all over the globe. Have all my older relatives retire. And build a dual ice hockey and ball hockey rink on a new land plot I purchase, which comes with a huge house. And lasers.

A, final answer.

I'd build my own private army.