Fantasy has long borrowed the idea of "another world" from myth, legend and religion. Heaven, Hell, Olympus, Valhalla are all “alternative universes” different from the familiar material realm. Modern fantasy often presents the concept as a series of planes of existence where the laws of nature differ, allowing magical phenomena of some sort on some planes. This concept was also found in ancient Hindu mythology, in texts such as the Puranas, which expressed an infinite number of universes, each with its own gods. Similarly in Arabic literature, "The Adventures of Bulukiya", a tale in the One Thousand and One Nights (Arabian Nights), describes the protagonist Bulukiya learning of alternative worlds/universes that are similar but different to his own. In other cases, in both fantasy and scie