Well of the Dark Side/Legends

The Well of the Dark Side was a volcanic crater on Mortis that bottomed into a lava lake. The Son resided here where he drew his strength in the Dark Side of the Force.

Upon learning that the Son was planning to escape Mortis, Anakin Skywalker followed the instructions of a vision of Qui-Gon Jinn to go to the Well and learn his fate. Skywalker heeded his old master's advice and rode his swoop to the bottom of the Well. There he encountered the Son, and was shaken by a vision of his future, committing murder as Darth Vader. From this point, Skywalker followed the Son in order to avoid these heinous acts, and they both left the sanctum of the Well.