What are some things that can be done with [large number] million dollars?

Most of us are familiar with what (your local equivalent of) $10 USD is worth, or $100 or perhaps even $1,000,000.

But larger amounts soon become unrelatable. And with the huge wealth inequality at play, it's easy to come across stories where something worth hundreds of millions was wasted.

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• How much money would it take, under our current systems, to solve various societal problems? (e.g. food shortages, infrastructure fixes, public health efforts, new transport)
• How much did the achievements of various organizations cost?
• What could individuals spend such money on? (luxuries, marketing)

And make sure to give evidence for your answers!