Everywhere you go these days you will see wind turbines. Some with 2 vanes, some with 3.
We saw some of these on our recent trip to the US
Are you a fan or a foe of wind energy? Probably a lot has to do with how close you live to one. Absence makes the heart grow fonder, right? Pros and cons. Renewable sustainable energy, lessening our dependence on fossil fuels. But the impact on wildlife, birds, humans? Jury's still out.
In any case, the construction of these giants is a pretty engineering feat.
Here's a promotional time-lapse video detailing the construction of one of these massive windmills. The embed code has been disabled, so I wasn't able to include it in this post, but you can watch it here on YouTube.