Dungeons are spread out across the maps and will not show until discovered. Generally located on the perimeter of the map, with the exception of Shifting Sands where four dungeons are located down the central line. There are 17 in total,
In order to earn the achievement you must complete each dungeon once. The secondary objectives are not a requirement.
Unfortunately simply discovering the dungeons is not enough, every dungeon has both a level requirement as well as prism requirement and on top of that in many cases you will be required to locate a number of power cells in order to open the dungeon door. Usually these power cells are located in the vicinity of the dungeon, however in the case of the Pit of Oblivion they are spread out across the map.
A video guide for acquiring those particular power cells will be at the bottom of the page.
The Following is a list of dungeons their location and level/prism requirement to access:Granite Steps:Tyrants Forge
- Level 25 Prisms needed - 75Lonely Basin:Pylon 512
- Level 3 Prisms Needed 1Cavern Rush
- Level 4 Prisms needed 4The Brood Hive
- Level 5 Prisms Needed 4Repository Blitz
- Level 10 Prisms Needed 8Crucible
- Level 13 Prisms Needed 8Proving Ground
- - Level 16 Prisms Needed 15The CradleAssembly
- Level 10 Prisms Needed 8Core Foundry
- Level 10 Prisms Needed 6House of Steel
- Level 25 Prisms Needed 10Shifting Sands Forsaken Halls
- Level 13 Prisms Needed 16Armory Flux
- Level 16 Prisms Needed 9 The Warren
- Level 16 Prisms Needed 15Acid Marsh
- Level 16 Prisms Needed 17Obsidian Run
- Level 16 Prisms Needed 11Coliseum
- Level 22 Prisms Needed 12 Pit of Oblivion
- Level 25 Prisms Needed 20
Pit of Oblivion Power Cell locations. Hope this helps I spent over an hour trying to find all the cells.