21 Mind-Boggling Optical Illusions That Will Melt Your Brain

15. Which Direction?

As this train comes zooming through the tunnel, it becomes a repetitive, blurred patten. And with that, depending on how you look at it, your brain has a hard time figuring out which direction it's going. Is the tube train coming towards you or traveling away from you? It's difficult to tell.

14. Uphill Waterfall

http://youtu.be/0v2xnl6LwJE This is a 3D model of Escher's waterfall by McWolles. M. C. Escher was a dutch artist who produced lithographs in 1961 showing a paradox where a waterfall appears to feed itself in a continuous loop. What makes the video so awesome is to watch it happen for real. View it in full screen and witness water do the impossible.