The Erdtree

The Erdtree is a gargantuan luminous tree located in Leyndell, Royal Capital. It is the symbol of The Golden Order and it derives its power directly from The Elden Ring and, at least prior to the ring's shattering, conferred upon the inhabitants of the lands a golden aura representing its grace. This grace is still present, however it no longer possesses the power it once had.

Description

The Erdtree towers over the mountains and hills of The Lands Between and can be seen from almost anywhere. As the physical representation of the Elden Ring, the tree may change its color or shape depending on factors that affect the Elden Ring.
The Elden Throne is where the entrance to the Erdtree can be found, and is where Queen Marika is imprisoned. The entrance is protected by a thick layer of thorns, which can be removed with

Show spoiler

the sacrifice of a Maiden at the Mountaintops of Giants, or with the use of the Frenzied Flame granted by the Three Fingers.

After the death of Godwyn and his subsequent entombment at the roots of the Erdtree, the roots themselves became corrupted and started infecting its victims with the "Curse of Those Who Live in Death".
Several smaller Minor Erdtrees also grow across the land, each of which is protected by an Erdtree Avatar.

"The Erdtree governs all. The choice is thine. Become one with the Order. Or divest thyself of it. To wallow at the fringes; a powerless upstart."
-Queen Marika the Eternal