Yggdrasil is also known as ‘the world tree’ and is a crucial part of Norse mythology. This is the thing that connects the nine different worlds.
The tree has three roots, one goes to Asgard where the Gods gather, the second goes to the land of the giants (Jotunheim) and the third goes to Niflheim.
By the first root there’s a well (Urd’s well) where the three Norns live. The Norns are the Goddesses of fate and spend their time spinning the threads of fate and dictating the future. They pour the water from the well over the roots of Yggdrasil and help to keep the tree alive. They also have the duty of placing a rooster at the top of the tree to ensure that the Gods are woken up each morning.
At the roots of the tree there is a dragon (Nidhug) who is enemies with the eagle who flies above the tree. Their feud is kept alive by the squirrel (Ratatosk) who spends his time rushing up and down the tree to inform each of the other’s hatred for them.
I’m not a Norse Pagan, but I have studied it a lot for a series of books that I’m planning. (Well, I wrote them many years ago and now plan to rewrite them some time in the future.) My interest for those books was in ‘Ragnarok’ which was an event in Norse mythology that could be described as the end of the world. Technically it was supposed to be ‘the end of the world as we know it.’
The Viking were a really interesting group of people. They came mainly from Scandinavia and were incredible at boat building and navigation. The word ‘Viking’ means ‘raiding’ and this was certainly something they were (and still are) famous for. They were a tough group of people who were used to living in harsh conditions and this is reflected in their mythology which often shows both the warrior culture and the harsh climate that they faced.
Generally most Vikings were skilled farmers and anglers and only resorted to raiding and violence when ordered to by their leader. Like the Celts they had a deep respect for warriors and had ‘Valhalla’ a place in Asgard where half of those who died in battle would go. The other half would go to join the Goddess Freyja.