'Korin's Tower' is a large structure located on Earth slightly west of Ginger Town and below Kami’s Lookout.
Here, players who are not of Saiyan or Namekian blood can talk to Korin at Level 35 or above to drink Ultra Divine Water and gain a substantial amount of EXP. (More when sipped instead of drank)
Players who die battling Imperfect Cell will respawn here, which is near Imperfect Cell’s “arena.”
Note: you cannot get this again from korin, even if you prestige.
Though Korin's Tower is supposed to be directly below Kami's Lookout, which is what the power pole is for, this is not true in the game.