Mythical worlds are imaginative realms often found in folklore, literature, and mythology. These settings are populated by fantastical creatures, gods, and heroes, each with unique stories and characteristics. Examples include the Norse realm of Asgard, home to gods like Thor, and the Greek underworld, ruled by Hades. These worlds serve as a backdrop for exploring themes of good versus evil, heroism, and the human experience. They often reflect the values and beliefs of the cultures that created them, providing insight into ancient societies. Popular mythical worlds can be found in works like J.R.R. Tolkien's Middle-earth and C.S. Lewis's Narnia.