Though not a continent, the Tunnel World in many ways functions as one. Its most distinguishing factor is that it is entirely underground. The Tunnel World is made up of an enormous series of interconnecting tunnels and passages; some natural - some carved. It is believed that the Tunnel World connects Drentae to Koaluckssie and eventually to certain portions of the Great Archipelago. No one has been able to find passage to Hughijen or Sulnuun through the underground labyrinths. There are some myths that imply that the former continent of Baelyndit was connected to Hughijen through the Tunnel World, but these connections may have been severed as Baelyndit disintegrated into the Great Archipelago.
Though no civilization seems to have originated here, several have moved here, typically seeking shelter from enemies or the nature of the surface world. The first culture that comes to mind when one thinks of the Tunnel World is the aldar. These albino elves moved to the Tunnel World very early in their formation and seem to have occupied every profitable location. The other well-known inhabitants are the vampires and other intelligent (or semi-intelligent) undead who are affected by the sun’s rays.