"LEONARDO da Vinci hid proof of ALIENS with secret messages in his paintings, according to conspiracy theorists."
https://www.express.co.uk/news/weird/834093/Leonardo-da-Vinci-PROOF-of-aliens-Mona-Lisa
"Lots of people think that the ancient genius Leonardo da Vinci was hiding secret messages in his paintings.
Some people think that he was hiding alien figures in some of his most famous pieces of work that can be seen if you mirror these images."
https://www.thesun.co.uk/tech/9446848/famous-artworks-aliens-and-ufos/
"Ancient Aliens: Da Vinci’s Forbidden Codes links the famous artist to extraterrestrials, through secretive codes in several of his paintings."
https://hiddenremote.com/2018/07/01/ancient-aliens-da-vinci/
"Leonardo da Vinci's paintings and sketches are examined in search of a possible connection to alien technology.
Might an examination of Leonardo Da Vinci's masterful paintings, highly technical hand-drawn sketches, and private journals reveal knowledge of otherworldly technology and extraterrestrial beings?"
https://www.ufo-blogger.com/2012/04/da-vinci-conspiracy-ancient-aliens-2012.html?m=1
Da Vinci’s ‘Alien Grey’ Image In The Mona Lisa Painting
https://www.ufointernationalproject.com/ufo-photos-and-videos/da-vincis-alien-grey-image-in-the-mona-lisa-painting/