In "A Very Old Man with Enormous Wings" Marquez uses fantasy to reveal human truths about the new beginnings and the value of humanity. In the story, the two most prominent characters are the fantastical Spider-woman and the very old man with enormous wings.
Spider-woman had a fall from her position in life and was in fact turned into a tarantula spider, with her own head and brain function. She, although in captivity of sorts in the circus (actually it may be a more protective environment for her...), found a way to establish a new beginning, and one of worth, by telling her story and teaching children to do what she failed to do, which is to obey their parents. The old man makes a new beginning, after his captivity, when his wings grow new, healthy feathers and he relearns how to fly and thus embarks on a new beginning.
Fantasy is used to symbolically reveal the value of humanity by imbuing the repulsive marginalized old, ill, dirty, disabled man with a majesty and greatness through the agency of his enormous wings and his angel status. Even though he is repulsive as a marginalized--unacceptable--person, few dare to deny that he embodies qualities of worthwhile value.