The Eternal Laboratory
The Eternal Laboratory is a area where players can take part in end game content (in the form of the Maps system).
It contains a device in the center of the area, simply called Map Device, that consumes a map item chosen by the player. When used, 6 portals to the map are opened.
Each portal can only be used once, and will be closed once you exit the map. This means you can only exit the map with 6 inventories of items. Opening a new portal inside the map will only move the entrance point to that position, instead of creating a brand new portal.