Well of Mimir

The Well of Mimir was a legendary magical well in Jotunheim, one of the layers of the plane of Ysgard, that was said to be a source of unlimited knowledge.

Location
This well was located near one of the roots of Yggdrasil,  sunk in a dark crevasse between two large hills where that root entered the land. One of the hills had a large cavern inside of it and the root reached into the Well itself, which had the appearance of a streambed and was encircled by pile of stones as tall as most humans or demihumans. The surrounding area was mostly barren and devoid of animal life, host to but a few scraggly weeds and stunted pines.

Powers
Drinking the waters of this well was said to increase one's wisdom. Additionally, one could find power keys near the well. Spell keys could also be obtained from the well, each tied to either a specific spell or plane of existence.

To drink from the well garnered a steep price to its guardian, requiring either the offering of an eye, a hand, a heart, or some other form of living sacrifice for each question. Alternatively, one could pay with a favor coin. A sacrificed eye could not be restored for no less than a wish spell, though its restoration would cause the individual to lose whatever knowledge they had gained from the Well for it. The head of the Norse pantheon, Odin, was said to have only one eye because he sacrificed the other in return for gaining secret knowledge from the well.

History
In the, a group of adventurers from the city of Ravens Bluff on the Prime Material world of Toril went on an epic journey across Asgard, Jotunheim, and Yggdrasil in search of the Well of Mimir so they could learn how to destroy a powerful githyanki artifact known only as the Great Machine. Their benefactors, the Ministry of Art, knew little about the Well's guardian but said that the knowledge it held was far greater than that contained within the halls of Candlekeep.

Notable Inhabitants
The well was guarded by Mimir the Wise,  an immensely powerful mountain giant who lived in the hill with a cave. He stopped all who would attempt to steal the well's power keys or drink from its waters without proper payment. Those who weren't a powerful giant or powers of the Norse pantheon were usually killed for bothering him, though he was willing to do business with anyone that presented him a favor coin.

Rumors & Legends

 * Duke Rowan Darkwood, a long time inhabitant of Toril, claimed to have drunk from this well.
 * According to the legends of the Norse pantheon, Odin buried the head of Mimir the god beneath this well after it was cut from the Norse power's body and that his great wisdom imparted upon the well's water.