Leonardo Da Vinci was quite possibly the world's greatest artist, as he was/is most popular for the "Mona Lisa" and "last supper." But what everyone from his time thought about his invention was that he was crazy, due to the fact that he wrote backwards and in Italian. Although people thought that he was crazy, some people actually built some of his sketches from his book (which had drawings of anatomy and machines inside of it) in real life. Here is a video of one of his inventions, a parachute.
This video shows that one of Da Vinci's inventions does work the way it's (probably) meant to work, this is also an invention by Da Vinci that was meant to help people fly, even though it only glides. If you want, you can click on this to find the video. Here is another video of people who built his armored tank, with a few modifications.
Yet another success for the inventor ahead of his time, Leonardo "of Vinci" (that is the translation for "Da Vinci"). Another link here. In conclusion, Leonardo Da Vinci is the worlds greatest inventor in history (really far back in it too).