The Signs of Ragnarok
-The death of the god Baldr, son of Odin and Frigg, and the binding of Loki.
-The three year long winter, called Fimbulwinter, during which the world will be plagued by war and brothers will kill brothers.
-The wolf Skoll and his brother Hati will finally devour Sol (the sun) and her brother Mani (the moon) respectively, after a perpetual chase. The stars will vanish from the sky, plunging the earth into darkness.
-The earth will shudder, so violently that trees will be uprooted, and mountains will fall, every bond will snap, freeing Loki and his son Fenrir.
-Eggther, watchman of the Jotnar, will sit on his grave mound and strum his harp, smiling grimly.
-The red rooster Fjalar will warn the Jotnar, in Niflheim another red rooster will warn the dead, and in Asgard, Gullinkambi (another red rooster) will warn the Aesir.
-Heimdall will blow his Giallar horn as loud as possible to warn the Einherjar from Valhalla, who shall fight the Jotnar with the Aesir.
-Baldr and Hod will be returned from Helheim, to fight with their brothers and sisters.
-Odin will lead the army of the Aesir and Einherjar to Vigrid, with Gungir in hand and Sleipnir carrying him.
-From the east, the army of Jotnar, led by Hrym, will leave their home in Jotunheim and sail the grisly ship Naglfar (made from the nails of dead men) to Vigrid.
-From the north, a second ship, will set sail towards Vigrid, with Loki, now unbound, as the helmsman, and the ghastly inhabitants of Helheim as the deadweight.
-Nidhogg will fly to the battlefield, and devour the corpses.
During Ragnarok
-Yggdrasil, the world ash, will shake from root to summit. Everything in earth and heaven and Helheim will quiver.
-Jormungandr, the Midgard Serpent, will emerge from the sea and engulf Vigrid as it sprays poison in all directions. Thor and Jormungandr will slay each other.
-Fenrir will break his chains and spread death and destruction, and will kill Odin, Vidar will kill Fenrir in retribution.
-Loki will turn on the Aesir, and fight with Heimdall; both shall be slain be each other.
-Tyr will fight the blood-stained dog Garm, Helheim's guardian, and they will kill each other.
-Freyr will be killed by Surtr.
-Surtr will finally set all the realms ablaze and they will sink into the boiling sea.
After Ragnarok
-Odin's only comfort about Ragnarok is that it will not be the end of the world completely. After most of the Aesir have died with the Jotnar, a new world will rise from the water. It shall be beautiful and green.
-Before Ragnarok, Lif and Liftrasir, a woman and a man, will have taken refuge in Yggdrasil. After Ragnarok, they shall repopulate the earth again.
-Several Aesir will survive, including Odin's sons Vali and Vidar, along with Honir and Vili. Thor's sons Modi and Magni will survive, and inherit Mjolnir.
-The few Aesir who survive will go to Idavoll, an untouched place, and shall build new houses and places. The greatest of all houses shall be Gimli, with a golden roof. There, the gods will live at peace with themselves and each other.
-There will be Brimir, a hall on Okolnir ("never cold"), where plenty of good drink will be served. And there will be Sindri, an excellent hall made wholly of red gold, on Nidafjoll ("dark mountains"). The souls of the good and virtuous will live in these halls.
-There is also a terrible place, a great hall in Nastrond, the shore of corpses. All doors face North and meet the screaming winds, and the walls are made of writhing snakes which create a flowing river of venom through the hall. This will be full of murderers and thieves, and after they die, the great dragon Nidhogg is there to feed upon their corpses.
Sources:
http://levigilant.com/Bulfinch_Mythology/bulfinch.englishatheist.org/b/Ragnarok.html
http://www.viking-mythology.com/ragnarok.php
http://norse-mythology.org/tales/ragnarok/
http://www.pantheon.org/articles/r/ragnarok.html
Poetic Edda, by Snorri Sturluson
Prose Edda, by Snorri Sturluson