It's one of the most polemic subjects of ever: is there more intelligent life in the Universe or not? There are, around the world, several theory supporters defending the existence of alien civilizations which are following closely the human evolution and that they even visit us occasionally since a long time ago. This supposition is fascinating but, if such a thing happens, where are the evidences of these visits? This is a delicate point: find a proof that an UFO visited us. The supporters of these theories, with the photography appearance, in the 19th century, won a precious assistant.