Greek mythology abounds in wonderful stories. I like most of them, but I have a top three of my personal favorites:
1) the legends about the cosmogony and cosmology, involving all those primordial gods that kept giving birth to other gods/goddesses, to titans and cyclops, leading to a large family tree;
2) the legend of Heracles and his 12 deeds;
3) the story of Jason and the Argonauts.