The Da Vinci Conspiracy - S4E8

Did Leonardo DaVinci leave secret messages in his paintings? As a youth, was he visited by aliens and given secret scientific knowledge...knowledge that he based his super-advanced inventions on? Why was DaVinci so secretive - so much so that we have no idea why he spent the last 16 years of his life on a single, seemingly ordinary portrait: the Mona Lisa. Did you know that DaVinci wasn't actually the first to codify some of his designs like the Helicopter, the Underwater Breathing apparatus, and the Tank, but actually followed a German named Talhoffer from early in the 15th century? And of course, our plucky Ancient Astronaut Theorists have aaaaaaaaall the accurate answers for us and don't base anything they claim in pure speculation...right? RIIIIIIIIGHT?! Let's prooooooooobe deep inside DaVinci...Renaissance style! (meaning no vaseline, of course)