It is believed that the company The McLoughlin Brothers (en.wikipedia.org/wiki/McLoughlin_Brothers) invented the coloring books. They published a book called The Little Folks' Painting Book in collaboration with Kate Greenaway in 1880.

There are rare instances of contour drawings of famous architectural structures and monuments with a variety of parts made in a realistic manner. Such coloring is complex to implement and is designed for adults.

Animals Kids Coloring Pages