If you've ever wondered how much work goes into all those visual effects you see in films, this video is a great example. Most of the visual effects you see you probably wouldn't even realise were visual effects. They're made to look so real nowadays that it's becoming pretty hard to tell.
The Great Gatsby is one fine example. If you've already seen the film you'd have most likely thought that those backdrops and buildings you see are real, well in fact they're all made up. It's just stunning to see how much work goes into films now and how real some of it looks.