Riordan Wiki

Yggdrasil (pronounced "YIG-drah-zill"), also known as the World Tree, is an immense cosmic ash-tree that serves as the home of the Nine Worlds and a means of travel between them. Yggdrasil's branches extend far into the heavens, and the tree is supported by three roots that extend far away into other locations. Various creatures live in Yggdrasil's branches.



It is not specified how exactly Yggdrasil came into existence, but it arrived with the Nine Worlds' creation, after Ymir's death.

Magnus Chase and the Gods of Asgard

The Sword of Summer

Magnus Chase, Samirah al-Abbas, Blitzen, and Hearthstone climb the World Tree to get to Nidavellir, but Magnus and Blitz are separated from Sam and Hearth when they run into the squirrel Ratatosk.

9 from the Nine Worlds

Speaking of Trolls...

Hearthstone climbs the branches of the world tree to get to Alfheim and save Inge.

Nice Doggy

Thomas Jefferson Jr. accesses the world tree via Alex Fierro’s room to get to Helheim and save his mother.

So’s Your Face!

After accidentally going to Niflheim, Mallory Keen makes her way through the icy landscape to Hvergemir, the hot springs at the world tree’s roots, and climbs up back to Valhalla.


in The Sword of Summer, Magnus described Yggdrasil's smallest branches being as large as an average redwood, while the biggest ones being wider than Interstate 93. As for the tree's trunk, it is so immense, that it just didn’t compute with Magnus. Each crevice in its surface seems to lead to a different one of the Nine Worlds , "as if someone had wrapped tree bark around a column of television monitors glowing with a million different movies."

Beyond the tree’s canopy nothing but a hazy white glow of the primordial Ginnungagap mist can be seen. No ground can be seen below either, only more branches crisscrossing the void.

The Nine Worlds


  • Yggdrasil's roots extend into three locations:
    • Urðarbrunnr (ON: “Well of Urðr”)[1], Hvergemir (ONr: “bubbling" or "boiling spring”), and Mímisbrunnr (ON: “Well of Mímir”). As seen in the Poetic Edda poem, Grímnismál, various creatures dwell within the World Tree, including:
    • Níðhöggr, a massive dragon/serpentine creature that gnaws at its roots, an unnamed eagle, the hawk Veðrfölnir, who sits between the eagle's eyes, and the four stags Dáinn, Dvalinn, Duneyrr, and Duraþrór.
  • The three Norns - Urðr (ON: “fate”), Verðandi (ON: possibly “happening” or “present”), and Skuld (ON: possibly “debt” or “future”) - attend to Yggdrasil, weaving the fates of both gods and men.
  • The Maya have their own world tree called Ceiba (pronounced "SAY-bah").[2]
  • The Hindu counterpart of Yggdrasil is Kalpavriksha, the tree from the Ocean of Milk that grants wishes.[3]
  • The story of Jack and the Beanstalk was inspired by Yggdrasil.


Locations (MC)
Nine Worlds: Alfheim | Asgard | Helheim | Jotunheim | Midgard | Muspellheim | Nidavellir | Niflheim | Vanaheim
Cities and Towns: Boston | Flåm | New London | Provincetown | York
Administrative Divisions: Connecticut | Massachusetts | New Hampshire | North Yorkshire | Sogn og Fjordane | South Carolina
Countries: Norway | United Kingdom (England) | United States of America (Confederate States of America)
Continents: Europe | North America
Other Locations: Alderman Estate | Bifrost | Blitzen’s Best | Boston Public Library | Bridal Veil Falls | Cape Cod | Charles River | Charleston Harbor | Chase Mansion | Dorchester | Fadlan’s Falafel | Folkvanger | Fort Wagner | Ginnungagap | Hotel Valhalla | Loki’s Cavern | Longfellow Bridge | Lyngvi | Morris Island | Nabbi's Tavern | Provincetown Airport | River Oure | Sessrumnir | Svartalfheim | The Thinking Cup | Vigridr | Yggdrasil