The library is located in Venice and was built by The Huntik Foundation to house a portion of their books having to do with Seekers, Titans, and magic.
In the episode "The Casterwill Client" DeFoe realized that the Huntik group would research the journal, so he had his group of Suits find the largest Huntik Foundation run library in Venice. This was so he could locate the team and retrieve the book, not to mention defeat Dante. Dante Vale, Lok Lambert, Sophie Casterwill, Santiago, and Cherit go there to research The Amulet of Will and they end up being led to Metagolem and Jodis Lore. In the same episode, DeFoe, Grier, and some Suits attack them here, only to be defeated. But, in the battle Sophie dropped a book that also led The Organization to Metagolem as well.