The answer is business. Let's say you work for 30 years, mean average you need to earn about 28,000 per months, it can be achieve if you are doing big business.
That's a lot of money we're talking about , well I think it takes a lot of time , maybe a lifetime of hardwork.But i've seen people achieve closer to that much of money by doing Forex Trading !
Bad question this one because of inflation. If you take inflation into account. When I was born 2,175,000.00 would be worth $10,000,000 now. Not taking into account bank account interest either. If you take the same rate of inflation into account it would take $4,597,464.50 of today's money to be worth what a millionaire is today, so ten million is not a good target
You must take it step by step Make 1k 10k 100k then 500k then 1 million and so on .. Hard work and being smart are ideal components ...