The Buddhists, following the traditions of their Indian fore-fathers, saw the universe as infinite in time and space, and filled with an infinite number of worlds like our own.
Above our ordinary world, there are two realms: the realm of form (rupa-dhatu) and the even higher realm of formlessness (arupa-dhatu). Below these is the realm of desire (kama-dhatu) which contains six domains (gatis), each with its own kinds of beings:
1. Devas or gods.
2. Asuras or titans (or jealous gods, or demigods)
3. Manusyas or humans.
4. Tiryaks or animals.
5. Pretas or hungry ghosts.
6. Narakas or demons (hell beings)
All of the above, even the realms of form and formlessness, are in samsara , imperfect existence, and therefore governed by karma and its fruits (vipaka).
The world extends around Mount Meru. Above the peak is the realm of the Buddha fields (or heavens). On the upper slopes you find the gods. The titans live on the lower slopes. Animals and humans live on the plains around the mountain. Hungry ghosts live on or just below the surface. And hell is deep under the earth. All this is surrounded by a great ocean.
Time in Buddhist cosmology is measured in kalpas. Originally, a kalpa was considered to be 4,320,000 years. Buddhist scholars expanded it with a metaphor: rub a one-mile cube of rock once every hundred years with a piece of silk, until the rock is worn away -- and a kalpa still hasnt passed! During a kalpa, the world comes into being, exists, is destroyed, and a period of emptiness ensues. Then it all starts again.
Some of the actors in the Buddhist mythological drama include...
Brahma -- the supreme deva, who convinced Buddha to teach.
Indra -- a major deva, originally the Hindu sky god.
PrajÃ±a -- goddess of knowledge. Buddhas mother was considered an incarnation.
Mara -- a deva associated with death and hindrances to enlightenment. It was Mara who tempted Buddha under the bodhi tree.
Yama -- the king of the 21 hells.
Nagas -- great serpents (or dragons, or water creatures). The king of the Nagas protected Buddha from a storm.
Gandharvas -- angelic beings who provide the gods with music