There is an serious argument that Vladmir Putin is one of, if not the richest man in the world:
How Much Is Vladimir Putin Worth, and How Does He Spend It?
The world’s richest man?
Rumor has it that Putin could actually be worth as much as $200 billion.
Finally, let’s address those rumors that Putin is, in fact, the richest person in the world. The rumors say that he is worth somewhere near $200 billion, which would make him twice as rich as Jeff Bezos. The problem, as we’ve discussed, is that nobody can verify his wealth. Putin has wealth hidden in all sorts of different assets — be it investments, real estate, vehicles, etc. — all over the world. He may very well have hundreds of billions, but nobody can prove it.
The argument is that the system has been rigged in a way so that the Kremlin's power grants Putin access to not just corporate wealth but the assets of other wealthy individuals under him, resulting in a net worth much higher than currently estimated. If he owns a considerable chunk of the most expensive assets of Russia, then it is not a large stretch of the imagination to assume he is actually #1.
This is all speculation of course since his wealth has never been verified.
"We will soon create intelligences greater than our own. When this happens, human history will have reached a kind of singularity, an intellectual transition as impenetrable as the knotted space-time at the center of a black hole, and the world will pass far beyond our understanding." -Vernor Vinge, 1983