In Norse Mythology the cosmos was split in to 9 realms.
Asgard
This was the home of the gods and goddess. These were the sky gods. There are many gods and goddesses in Asgard. They are called the Aesir.
The chief god was Odin. He was married to Frigg (also called Frigga) the queen goddess.
The Aesir were the dominating gods in Norse Mythology. All the gods and goddesses had magnificent mansions in Asgard.
Vanaheim
This was the home of the Vanir gods. The Vanir gods are an old branch of gods. The word “heim” means home. The Vanir were masters of sorcery and magic. They are also widely recognized for their talent to predict the future.
After the war between the Aesir gods and the Vanir gods, three of the Vanir came to live at Asgard. Freyja, her twin brother Freyr and their father named Njord.
Nobody had mastered sorcery better than Freyja. She was the one who taught Odin the secrets of magic.
Jotunheim
This was the home of the Jotuns, the giants. They were the sworn enemies of the Aesir. They lived in the mountains.
The world in Norse Mythology was created from the corpse of the first Jotun, namedYmir.
The Jotuns and the Aesir were constantly fighting, but love affairs could also occur. Thor and Odin had lovers who were Jotuns. Freyr married a Jotun. Njord also married a Jotun woman, though not by choice.
Loki was a Jotun who was accepted by the Aesir and lived in Asgard. In the end Loki does turn against the Aesir showing his true nature.
There was a river called Ifingr which separated Jotunheim, the home of the giants and Asgard, the home of the Aesir. The river was fast flowing and therefore never froze.
In Norway there is a mountain range called Jotunheimen. The 29 highest mountains in Norway are found in Jotunheimen.
Niflheim
This was the dark land of mist and cold. It was in the far north. This was the lowest of all the nine worlds. The home of the dead was in Niflheim. It was ruled by Hel. It was a gloomy and pitiful place. All humans who died of old age or illness were sent to live in Hel in their afterlife.
One of the three roots of Yggdrasil ended here in Niflheim. The serpent named Nidhogg resided here. He not only gnawed on the root of the tree, but also took pleasure in eating corpses.
Alfheim
Alfheim was the home of the light elves. Their home was right by Asgard in the heaven. They were beautiful and auspicious creatures. They were considered the “guardian angels” in Norse Mythology.
The light elves were certainly a good omen.
Freyr was the god of fertility, but also associated with the light and the sun. The gods gave Freyr Alfheim as a teething present.
Svartalheim
This was the home of the dark elves. They lived under the ground. They were hideous and could be a great nuisance to the humans. The dark elves were nothing but trouble.
Many believed dark elves were also responsible for nightmares. These dark elves were called mare. A mare would sit on a sleeping person’s chest and whisper bad dreams to haunt the poor soul. A mare could also haunt animals, especially horses.
The dark elves could not be exposed to sunlight. If the sun’s rays reached them they immediately turned into stones.
Nidarvellir
This was the home of the dwarfs. They lived under rocks, in caves and underground. They were masters of craftsmanship.
The gods of Aesir received many fabulous gifts from the dwarfs; the magical ring, Thor’s hammer, and the amazing ship are some examples of their outstanding talent of craftsmanship.
The dwarfs stayed underground during the day as they would turn into stones if they were exposed to the sun. The dwarfs could not always be trusted and could be trouble to the gods and the giants.
Midgard
Midgard was the home of the humans. It was mostly populated by the Sons of Heimdall. The humans were constantly exposed to the gods, goddesses and creatures from the other worlds in Norse Mythology.
It was Odin and his two brothers who had created the humans. A rainbow bridge called Bifrost connected Midgard and Asgard. The gods frequently travelled across Bifrost.
Muspelheim
Muspelheim was the land of fire. It was ruled by the giant Surt. He was a sworn enemy of the Aesir. It was located in the far south. It was the first land of existence.
Surt will ride out with his flaming sward at Ragnarok, the end of the world. Surt will kill Freyr and set fire to Asgard, turning the home of the gods into an inferno.