While the movie overall is great, Superman returns has to have the dumbest Lex Luthor of them all.
Not only does he not help to push humanity forward in the slightest, but his goal is to create a landmas of radioactive crystals.
Even if I assume he didn't know they were radioactive (That would still make him stoopid). what exact use do you expect to get from a huge crystal? Because if you think you're going to grow food in there, good fucking luck 
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@LukeAlmighty Getting soil on the crystal island is trivial next to making a new landmass in the middle of an ocean. And considering how many states have started making artificial islands all over the place, clearly there is some demand for new empty landmass, that you can build on however you want, without pesky environmental restrictions.
Haven't watched the movie in a while, so I don't remember if this was an one-off achievement, or if Lex could have made more islands if he wanted. If it was the latter, then he'd definitely be able to make a business out of creating crystal landmass.
@alyx
Getting soil would be trivial if the continent was on a normal world, but he also wanted to raise the sea levels. And while something like the waves killing billions would be ridiculously evil, the insane part is, that you have a "fertile ground" only in places where there was just right amount of water both before and after the flood. So, pretty much nowhere.