"The golden age" of coloring books is believed to be 1960-s, because almost all characters were depicted in them, as well as some products (like Planter Peanuts or Campbell Soup)

The picture should be large without small details, images must be recognizable, kind and interesting, for kids contour lines should be thick, it hides some errors made by child, the outlines of the pictures should be smooth, without corners, difficult bends.

Eiffel Tower Coloring Sheet