|Terramar Racetrack, Sitges Spain|
The story is that it was built, they had a race, they ran out of money and the racing stopped. There's a lesson about capitalism here, but I'm not sure we'll ever learn what it was. I suspect it was something on the order of biting off more than you could chew, but there could have been some skulduggery going on, or maybe the market was saturated. You'd think with such a massive investment they would have found a way to keep it going. That fact that they couldn't means they probably shouldn't have built it in the first place, but that would mean knowing what is going to happen, and no one knows that.
Wikipedia has a page.
Google found a bunch of sites.