Notice how the sun is watching and the moon is sleeping.
The human quest for knowledge in one image!
The Flammarion engraving is a wood engraving by an unknown artist that first appeared in Camille Flammarion's L'atmosphère: météorologie populaire (1888). The image depicts a man crawling under the edge of the sky, depicted as if it were a solid hemisphere, to look at the mysterious Empyrean beyond. The caption translates to "A medieval missionary tells that he has found the point where heaven and Earth meet..." (Source) I suspect it is modern colorization of this woodcut.
