Looking to invest? Look no further than a Mushroom Kingdom question mark block, the most secure vault ever created. Unless you punch it from underneath, hit it from the side with a cape or tail, or throw a shell at it.

These things are more like donation boxes for Mario's "Save the Princess Again!" campaign than checking accounts.

We've never had to think about the conversion rate between Mushroom Kingdom coins and US dollars before, but then again, we're not economists. What do you expect?

Would you store your money in a question mark block? Let us know in the comments or on Twitter.