Reading Room

The Reading Room is a place outside of the Parallax which ties all the worlds together and grants access to every world by means of the Orbs.

Description
Otto described the Reading Room as "the font of all knowledge to the entire Parallax since time began". He was referencing the fact that once a Guardian had entered the Reading Room, they could use their Stave (which turns gold while in the Reading Room) to view, learn about and enter other worlds.

Trivia

 * The Reading Room is where Ben and Katherine discovered side portals.