This achievement requires you to unlock all 15 locations. You will have to reach at least level 21 in order to unlock the last two. Many of the levels also require you to complete intermediate quests (such as finding or buying specific items), eliminating certain creatures blocking the entrance, or repairing a structure to make a path to them (e.g., you need to rebuild a bridge to the bottom/center part of the map to unlock the area where the Stronghold and Bog are).
The locations are:
* Forest Cabin
* Fisherman's Hut
* Old Town
* Farm
* Stone Quarry
* Menagerie
* Forge
* Stronghold
* Dwarf Caverns
* Ship Graveyard
* Bog
* Floating Isles
* Mage Tower
* Fairy Glade
* Sunken City